The reason you don't really see it is because less than 1% of men are able to pull it off. And of those 1%, most aren't marrying these women and wifing them up because they are players and want to keep banging new 20yos as often as possible because they CAN, and that's yet another reason you aren't seeing them together.
There are far more 1% men on this forum than in the real world because we are here and understand the way things are. That means that you should not say that you can't do what 99% can't do. You have the tools and knowledge to do it; whether you choose to take action to make it happen, or try to use seeing the blue-pilled 99% not doing it as an excuse for yourself as to why you also can't do it so shouldn't even try is up to you. I can tell you which of those two options is going to get you results.
I am 46. My girlfriend of one year is 36. Prior to her my GF was also 10 years younger than me. Prior to her I was 44 and dating a 23yo professional ballerina. Prior to her I was dating a 23yo college student. When I was 34 I married a 24yo. After our divorce when I was 40, most of the women I dated were in their 20's and just a couple were 30-31. If you have taken the red pill and know how to pick up on IOIs, you will notice that women of ALL ages give them to you. I see 15yo girls giving me IOIs and women in their 60's giving me IOIs. I'm obviously not going to act on either of those demographics but the point is, it happens and it happens regularly. Self-limiting beliefs and excuses won't help anyone get laid by women in their 20's.
Men in their 30's through 50's and even 60's can look very sexy to women of ALL ages. You need to have your look and your vibe. You need to have good style and look sharp. Good hair if you still have it. Good physique (big muscles are great but if you can just keep the fat off, have a V-shape, and have SOME muscle tone that is more than enough - anything else is bonus points and the law of diminishing returns applies). Exude confidence. Look happy. You aren't likely to get IOIs from women in their 20's if you are out there wearing sandals, basketball shorts, a t-shirt and a baseball cap. To give a personal example of what I wear, in summer it will usually be something like loafers or boat shoes, nice cotton dress shorts with a ~7" inseam, a button up short sleeve shirt (often linen), my hair slicked back and a very nice pair of sunglasses that fit my face.