I don't mind the reminiscing and may indulge in it myself at times
; being relevant imo means being able to relate the olden days to today, to listen and interpret something through the lens of experience rather than holding a mirror up to one's self as if that is the end all, and to pick up on social cues.
This potential "irrelevance" is certainly not limited to seniors as has been somewhat rudely put forth and ironically exemplified elsewhere on this thread (not by you). But not all of us are interested in being relevant at whatever age--sitting back quietly while listening might be a good thing. I rarely learn something when I am the one talking.
Speaking of listening--I was seated a couple of months ago in a noisy restaurant next to someone a couple years older than I who pretty much dominated our conversation. As the dinner wound down, he mentioned that his hearing aids were not working properly. I think in some cases "seniors" with hearing loss might come across as irrelevant when actually there is a simple communication problem.