Not really. Gaming is as strong as always.
Consoles are as prevalent as they've always been, as are PCs (despite people declaring computers dead due to Tablets for some time). Hell, the 3DS is Nintendo's best-selling handheld
ever, and that came out
during the Mobile boom. The increased use of the simplified devices (Phones, Tablets) hasn't translated over to their competing devices falling by the wayside by a longshot, nor will it - people do not buy a phone primarily to game. They don't even buy a smartphone primarily to game. They buy it to do phone shit, and to a lesser degree, Internet. Gaming is simply a side-benefit. This is true of tablets, as well; outside of artists and schools, the biggest market for tablets are offices and businesses, who - again - are not buying them primarily to game.
Meanwhile, gaming console sales, in spite of an economic recession, have remained fairly solid, and indeed, picked up strongly over the last few years, and PC gaming is as strong as it's ever been. The people going on about how mobile and such are the next big thing are ignoring that it's fundamentally a different market than the market for console gamers or PC gamers. Mobile is successful in their own right, and that's cool, but it's a logical fallacy to say that they'll supplant the market when they achieve fundamentally a different niche.
This plurality of markets is awesome for people who like games regardless of the platform they're on, but it's
a fucking death knell for any ideological shit-stain trying to claim that the gaming industry as a whole must change for the sake of diversity and point to the iPhone as the herald of the end times for other platforms.