Obviously it depends on the person.
Some people just blow through the newest games as soon as they come out, then never touch them again and instead just wait for the next gen.
Others play and re-play and re-re-play the games, whatever gen, whatever order, whatever they're in the mood for at the time.
Still others "love" one gen and play it over and over and "hate" another gen and would never even consider playing it, no matter what.
And most are less extreme than any of those - they just play whatever they play whenever they play it.
I'd say that the 5th gen will be as "relevant" as any of the others - some will hate it and never miss an opportunity to complain about it, others will love it and never miss an opportunity to sing its praises, some will replay the games over and over, and others will lose their cartridges and wonder years from now whatever happened to them.