In terms of what is considered attractive I think men do have a longer shelf life. Just look at the stark contrast between adjectives that are used to describe older men vs women. Distinguished, suave, silver fox, mature, bachelor vs hag, crone, frump, mutton, granny, spinster.
Do you remember 'THE 100 Sexiest' Lists in magazines? Half the list would be men 40+ as voted for by women. The sexy women list would be full of women under 35 as voted for by men.
There is the famous saying in Hollywood about women not landing roles after 35!
I wouldn't know about the gay dating scene so I can't comment. But from dating online when I was single at 24 I put my preferred age range from 28 to 45. If I were to become single now at 34 I would put my age range at 38 - 50. If I were to become single at 50 I don't think I'd bother at all! But if I did, the range would be 50 - 60.
This is what I mean by the dating pool shrinking for women in particular, as the majority of women don't care to date much younger men whereas men often do.
I remember dating profiles of men in their 60s with minimum age requirements of 25! God loves a trier! 😑