Earlier of this month when the gameplay of Baldur's Gate 3 was shown, the overall reactions are mostly negative. While not surprising, given that it uses the same engine as Divinity games before but most people are disgusted with it and decided to boycott the game and its developer Larian Studios as two previous BG games aren't turn-based. Some went far as labeling all turn-based games as irrelevant and "outdated".
While I don't think any turn-based games or any genres are outdated but I can understand the situation. Some games with TB roots have abandoned it such as Final Fantasy XV, Front Mission and New Sakura Wars in order to appeal newer generations of gamers. Although the upcoming Final Fantasy VII Remake will have turn-based mode but it nothing to its 1997 original. In fact it's more like a glorified version real-time with pause instead as pure TB are no longer relevant with modern graphics, at least what its creator Tetsuya Nomura claimed.
Turn-based games won't die anytime soon despite its declining popularity(in fact more of them are being made for PC by independent studios) but lots of people can't wait to bury it for good. There are two major reasons for its declining of popularity in today's generation of gamers. First as mobile phones becoming more and more powerful and able to run more graphically demanding games such as Playerunknown's Battlegrounds, Fortnite and many action RPGs. Before that most mobile phone games are simple puzzles,line battles(a subgenre to tower defense) and if they were lucky enough they get to play some turn-based JRPGs. Today with PUBG and Fortnite dominates the mobile gaming, turn-based JRPGs are no longer fun to play anymore, even by mobile phone standards. Second is the rise of video streaming. Average turn-based games like Persona and XCOM are not as fun to watch than average action games. As an analogy it is much like watching your father fixing his car in the garage. Sometimes you got to see something interesting but at most of time you don't. An average action RPGs and FPSes are more fun to watch even if you don't really like the games at all, much like watching a basketball or football game in real life, which is much better than watching your father fixing his car in the garage. I myself might watch the single player mode of Call of Duty in Youtube even I had zero interest on the games.
An average FPS game still plays much like its 1990's predecessors such as Wolfenstein 3D, Doom and Duke Nukem 3D. Average action RPGs don't evolve much since 1990's either. Average platformer still plays much like Super Mario games with some variations due to copyrights. Classics such as Tetris, Pac-Man, Frogger and Bomberman almost never change for decades and in fact that is why we loves them. We probably hate them when they took completely different direction like Bomberman: Act Zero in 2006.
Why some individuals like Tetsuya Nomura and some others claimed that turn-based RPGs are no longer relevant in modern times anymore? Marketing gimmick. Contrary to him turn-based JRPGs still sold very well despite declining in popularity. The latest installments of Persona and Dragon Quest series sold by millions. Atelier series also sold well despite being almost yearly releases. Judging by sales alone, turn-based JRPGs won't die anytime soon, just like any other genre.
I believe everything else depends on our perceptions than anything else as well as marketing gimmicks. Some genres will survive as long as there are fans just like turn-based RPGs despite declining demands and popularity outside PC platform.