Retro has always mostly been a feeling than something concretely defined by the amount of time passed. If you're living in the middle of the explosion of technology as far as video games go, then things can seem "old" really fast. If your current level of game graphics is Tekken 3, then Super Mario Kart from a few years ago is already going to look like an out-of-date game that only "retro gamers" are going back to. If the biggest RPG right now is Final Fantasy X, then Chrono Trigger from 7 years ago is already a retro game that only hardcore gamers are going back to play.
Graphical technology has nearly plateaued for over a decade now, so nothing released since like 2014 feels retro anymore. Some would say nothing since PS3/360 counts as retro, since even early HD games could be seen as closer to modern graphics than SNES games are to late PS1 games. There's nothing odd about "going back" to playing a game from 8 years ago that looks like it could have come out just recently. In fact, a lot the most popular games with normies now are live service slop that's often close to a decade old by now and has just been getting updates since then.