I do agree that it's nostalgia-powered and fuelled by millennials with disposable income being a fertile market, but to me here's the weird thing: I think pixel art can look incredibly beautiful while the old early 3D game style looks like absolute ass (such as the OG FF7 screenshot above).
But I grew up much more on the latter than the former. There has to be more to it than just nostalgia.
I've been wanting an action RPG Pokémon forever but this does not make me excited. Also not keen on buying Nintendo products anyway.