>>52249963I think it took Red and Green a summer, personally. In Japan Summer vacation is like, one month, and I think that's a fair estimate. Maybe it took 2 months, but I doubt it and I think even 3 is pushing it. RGBY do not feel like they take very long.
In RSE it is hard to say. Dewford is tiny as fuck and yet it is based on Tsushima, which we know can be extrapolated into an entire game in and of itself. So who knows? I think part 1 happens over the course of at least a few weeks, and may have taken several months in and of itself. I have no time frame for the second half of the game. I'd say all in all, maybe it took 6 months to a year.
DPPt doesn't feel like it takes a very long time. Maybe 2~3 months.
BW is hard to say, I don't remember much. As a kid, I used to say it took 10 days because of the thing where the npcs apparently left black/white city/forest if you didn't beat it in 10. Not sure if that's true but whatever. The seasons change in BW, which makes it hard to tell. But because of how urbanized the region is, I don't see why it would take a long time.
GSC is difficult to say because it has two credit rolls, and it's the most laidback game in the franchise. I could see six-months to a year passing between Gold/Kris vs Red, but the Johto League could have been done in less time.