If you mean this gen specifically then it's 10 years as its predecessors , though last gen was an exception cause of the weak specs. If you mean before the release of next generation then 6 years sounds healthy cause of different factors , one of them games just can't get cheaper and rely on sales cause it's an unhealthy practice and they wanna avoid it as much as they could by re-releasing the enhanced version , 7 years is just too long before releasing the next big hits , most of us got sick of waiting all because of that and it's not worth the wait especially games are just getting more expensive and they just keep changing rapidly, both hardware and contents should advance simultaneously, contents are declining and anyone can't deny this fact , look back in 6th and 7th gen , hitter titles got sequels in the same generation, why this is not happening anymore? Technology got more advanced with ai , it's doable to offload human tasks and rely on ai instead of human especially in crunch time.