Except the switch hasn't reached the numbers of the DS and this is without adding the 3ds numbers to it.
Not only that Nintendo is making large investments for mobile phone games themselves because the mobile phone game market has grown far larger in Japan than consoles by comparison. You keep pushing the mobile phone narrative as if mobile phone gaming is an illusion, but Japan itself makes up around 1/3rd of all mobile phone game sales globally. The Switch is only doing well in Japan because it's a portable and that's pretty much why. And looking at what games on there, 6 of those entries are pokemon and 5 of those are final fantasy. You don't really have a diverse amount of IPs among those listings. Final Fantasy 16 and Dragon Quest are both owned by Square and Square has even mentioned that they're focusing on global releases for everything. We already know PlayStation is getting both Final Fantasy 7 Rebirth and Final Fantasy 16 and it's sounding like they'll be getting Dragon Quest titles as well. Monster Hunter isn't skipping Playstation either. The titles that are not on playstation are either fully owned by Nintendo or have partial ownership like Pokemon. The Switch has already reached saturation and it's looking like Nintendo is going to be prepping new hardware because it's even fallen behind the Xbox on the NPD charts.
Sony itself also has done better with it's more recent first party offerings like God of War Ragnarok which has broken all previous records by first party Playstation games. Their first party Japanese games never did do as well as third party Japanese offerings(outside of GT). But historically their western first party titles always did better compared to their Japanese counterparts. Even since the beginning when Naughty Dog developed Crash and then later on the PS2 with Jak, then you had insomniac with Spyro on the PS1 and Ratchet on the PS2, and then Naughty Dog again with Uncharted and TLOU for the PS3. God of War had a very middling installment on the PS3 and now you have 2018 and Ragnarok now making up the majority of the series sales even though these games only existed within the last four years and the first GOW game came out in 2005.
Man, do I
always have to bring up this point
I'm not defending Sony, but I've kept watch on their business since I could get a subscription to a gaming magazine in the 2000s. Sony's nails in the coffin started when Ken Katsuragi quoted in 2006, and I quote: "The PS3 isn't a video game console, it's a computer".
Sony's problems aren't that their Japanese IPs are underselling. It's the fact that Sony has been just as fucky and mismanaged as Nintendo and Sega and the rest of them in its own, special snowflake fucky way. Sony's problems are as what a famous nigra said (Bill Cosby): "Don't try to please everyone. If you do, you'll please nobody."
You bring up their Western IPs being financially successful, but I hate to break it to you: their reliance on third parties and "mainstream appeal" has very fickle staying power. They don't have a "core fanbase" anymore. The crowds they wish to appeal to have behaviors and cultural shifts and underpinnings they just leave up to their overseas divisions and say "FUCK IT", which are way more different that what they have back in Japanland. Appeasing with Nigger Squirrels for the PSP was another nail in the coffin by the way.
You know why I bring up their JRPG Trifecta of Wild ARMS, Popolocrois, and Arc The Lad? Because that shit was
successful. Again, a-fucking-gain, Sony managed to pull off the hail mary of video game project pulloffs that not even fucking Square could do with Legend of Mana, Final Fantasy IX, and their "Millennium Playstation" projects. Oh sure, yes, you can bring me the dividends and profits and estimated returns, but along with the JRPG Trio and Dark Cloud, Sony did have an in-house studio that could had rivaled Nintendo's or even outdo them.
As much as Nintendo has laughable spergs and super autists like Bob Chipman and Chris Chan, they get to have the last laugh because they know how to keep their audience around. I've heard and acknowledged before that though Rated M For Manly and Mature Because I'm A Big Kid Now games have a lot of appeal, they do not have the kind of welcoming face appeal that mascots and cutesy or more lighthearted heroic characters have that don't make people think if their brand is made for serial killers and broken mentally ill people. About as much as I hate moral watchdogs and moral majority child fucker cumsuckers, there is a point to having a more approachable and friendly side. By the way, Sony's only official designated mascot was Polygon Man. Oh, you don't know who he is? Well here, have a look.

And we wonder why Sony's got its rep. That's another nail in the coffin too!
And you know, let's go straight into the meat of this and evicerate the entire fucking thing. We'll start with Grand Theft Auto and Rockstar. As much as I am a big fan of Vice City, their affairs with Sony have given us the lesson that you shouldn't have your eggs all in one basket, and the aforementioned lessons above. As much as it is important to keep around a crowd for Mature Because I'm A Big Kid Now games, they also tend to be a part of the fleeting mainstream crowd, because that crowd usually includes people who grow out of video games or don't come back, for one reason or another (ie a dubious crowd of so-called people who may or may not be involved with criminal activities ie niggers). GTA3 may have gotten Sony on the map in the States, but that's just a stimpak boost with a withdrawal aftermath that was never treated. Sony was reliant on them even when GTA 4 was a fucking puppet show and when the series just snowballed into the 2010s. And then we have Naughty Dog, with Crash Bandicoot. Same story. As much as I harp on Nintendo for being idiots with their third parties, Sony has the opposite problem, which is just as bad. Another fucking nail here! Or two!
And speaking of niggers, we come back to the PSP. If you ever asked me my opinion on this matter, I can outright say the PSP was the worst handled and managed video game console ever, and that how it was handled should be in the history books to know how to not fuck up having a relatively great product. From fucking Nigger Squirrels, to pushing movie UMDs, to presenting it to the nigger side of the audience that it was a "Playstation on the Go" like dead weight with no impact. Without mascots, without new interesting games exclusive to it, without good promotions and targeting the kind of audience that would stay, the PSP died because the audience overseas it was directed to and diverted all resources to didn't give a fuck.
And then we have internal affairs. That is a fucking shitshow in itself. Sony works on the good ol' Imperial Japanese system, in that all branches are made to compete against one another, than to help and coordinate with one another. While compeition is a good morale booster and helps to relieve tensions, making your own company its own gladiator arena of business is a great way to fuck yourself over. NO ONE works with one another, NO ONE notices something fucky that needs outside feedback and output, and NO ONE builds upon each other's strengths. Fuckin' wonderful. Is it any fucking reason why we got Ghostbusters 2016, SJW "story games" propaganda, and The Last of Us 2?
I'm really surprised Sony is still alive, limping and carrying its maimed and battered body down the road it's on. While I'd keep on using that nail in the coffin metaphor, that fucking coffin is way too big for enough nails to put Sony into yet. There's also a lot of other shit I did not cover in this, but the main point is the video games business than anything related to its online shit, and that Sony traded in its millstone for donkeys and mules that were bound to run away or die because they didn't take care of them or notice good enough. And that road ahead? They're on that path alone now, with the crowd it blindly chose to be with: a bunch of fucking lowlife thieving conartist clowns, carnies, heathens, and gypsies.
Good fucking morning to you all. I'm done now.