The fandom just kinda awkwardly ignores how this game should definitely be finished by now considering that it has teenagers who would've been eight years old when chapter 1 came out and 5 when UT itself released, all just because it releases in chapters. Hell, I gave Silksong a lot of shit back in the day for going on so long with way less communication, but after seven years it came out complete and with DLC on the way instead of taking a little under a decade to be only half-done. (and while I like the game I'll say its replay value is actually pretty weak if you already know what's going on,
I'm not much of a video game player, but I played Undertale when it came out and it felt really fresh. The battle minigames were fun, the setting was novel and playing it blind meant the twists were surprising. Deltarune does not, because it's reheated Undertale.
It's in Toby's interest to have a prolonged development cycle. The absolute monstrosity of his fanbase remain engaged because it's lorebait, so they're constantly speculating about how the plot will go. He'd primed his fanbase to continue with Deltarune by making the game with the same characters but in an alternate universe and ooh are you going to meet alternate universe Papyrus in
thiiis chapter? Are lesbian science lizard and lesbian fish knight going to end up together in
thiiiiis chapter? Is funny skeleton man going to reveal he's a dimensional traveller in
thiiiis chapter? And so on, and so forth.
The longer he drags it out, the more he'll keep making money. Toby's a bit like (a talented version of) YandereDev in that regard, who realised his fandom will only throw money at him until the game's actually finished, and he won't know what to do next once he's actually completed the game. As far as I'm aware Toby's not even actively developing the final chapter. The moment the game's finished and lore is "answered" is the moment the fandom gradually starts winding down instead of buying multiple outfits for their Ralsei plush.
I'll admit I did find the queen pretty amusing, but the overall setting (schoolchildren with magic powers who have to save the universe, and their toys etc come alive in their magic alternate world) is far too childish to my tastes compared to Undertale, which at least presented a consistent fantasy world.
and also I don't know why people keep interpreting its in-universe time period as like the 2000s because of Noelle's website when the way everyone talks is distinctly contemporary, especially in the first 2 chapters.)
It's definitely designed to evoke the late 90s/early 2000s, based on them having a "computer room" with CRT monitors

and a big CRT TV and non-cordless landline

and there's references to things like Petz II. The game just also has completely contemporary sensibilities and memes, because it's trying to mine the nostalgia-bait angle while also subsist on brainrot.