It's only older people who think youth equals attractive. Young people don't think that, because that's their norm, so to be an attractive young person (to your peers) you need to either be properly good looking, or put a lot of effort into elevating your looks.
I don't think that's true. I have a 17 year old. I was a 17 year old. I think younger adults, are fully aware they are considered more attractive just for being young.
A few women I know who have dated younger men have had terrible things said to them by younger women, who are incredulous the man they fancy have picked older woman. And comments from their boyfriemds male friends who assume they friend must only be dating them because they are 'good in sack'.
Yes some young people are attracted to older people, but it's usually due to other things other than looks alone. Things that make them attractive buy not just because they are 'hot'.
Obviously not all young people. But I don't think youth, is only attractive to older people. Also, people are having anti ageing treatments younger and younger to try and preempt aging.
I work with quite a few women late 20s and early 30s. More of them are having botox than the older women. Because they are concerned they won't be attractive when they get older.
Look at celebrities. Jlo doesn't look in her 50s. It doesn't pass young people by taht she is attractive because she doesn't look 50.