I would say around 6 years is good.People need to realize that game development and hardware costs are taking more time to make/go down.We not only need longer generations so that the system get games, but also because it is no longer possible to release full generational leaps in 4 years at a "low cost".
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1







