Replaying EarthBound made me realise that retro games have existed pretty much since the moment that “retro games” was a meaningful concept.
No, seriously. Like, look at the soundtrack. EarthBound didn’t have to have music made up largely of synthesised drone and chiptune bleeps - the Super Nintendo was capable of producing naturalistic instrumental sounds. Indeed, EarthBound actually uses them in places - sometimes it even flips from chiptune bleeps to naturalistic instruments mid-track for dramatic effect. (Check out this track for a great example - the transition is around 0:53.)
The deliberately limited colour palettes and low/no-animation sprites get in on the act, too. Heck, even the user interface plays around with retro aesthetics; it’s got one of those old-school CRPG UIs where you have to stand next to whatever you want to interact with, then bring up the menu and select the appropriate action from a list of verbs - except not really, because it also has a context-sensitive “interact” button that just picks the most appropriate action for you, in the mode of modern CRPGs. The whole antiquated interface is purely for effect.
And this was still early in the Super Nintendo’s lifecycle - it went into development at about the same time the console first hit the shelves. Literally the very moment it was possible for ironically retro NES aesthetics to be a thing, somebody went and made a game with ironically retro NES aesthetics.