Elder Scrolls III was released in 2002. It was a fraction the scale of Oblivion, which was a fraction of the scale of Skyrim. You could beat the game inside 40 hours. I would give you 10:1 odds we see similar - if not more expansive - open-world single player RPGs like this published inside the next five years. Hell, we already have a number of them in development.
FFS, The Witcher 4 is due to land in 2027. Cyberpunk 2 is targeting 2030. Divinity is getting an open world adaptation, with a workforce of over 500 professionals over at Larian Studio, with an early release scheduled sometime in the next year or two. Guild Wars 3 is in the pipe as is a Runeterra MMO from Riot.
And that's not even getting into all the titles coming out of the burgeoning Chinese studios - Black Myth, Honor of Kings, Genshin Impact. It's a deluge. We have more titles being released annually than anyone could dream of playing.