Let's clear the field and say that 2nd video mostly relates to western culture, and the first video to a lesser extent. With that out of the way, let me clarify one of the big reasons why guys in Western countries watch **** well into their 20s and perhaps even beyond.
I talk specifically about younger men and younger women - in their teens and 20s in Western countries. Women are primarily attracted to alpha males (and note, the definition of alpha male is what it means to be alpha in the evolutionary sense, not in the modern sense of wealth and power - though that does happen at later points in men's life), which form perhaps 10-20% of the whole male population. These guys will get sex by the droves each day and each week. Probably 50-80% of women will have sex with these men, and occasionally with other men but nowhere near as much. Most guys at that age are less confident socially as well, making it more difficult for them to get sex. This is one reason why **** is so much in demand in these countries. It's not as simple as saying guys should start looking for natural sex when it's difficult for them to get girlfriends.
Ultimately, for young women, having so many sex partners throughout their youth results in them becoming bitter with men and having high expectations from future male partners. Bitter because the alpha males they go after tend to be not as interested in long term relationships because they can easily get other women, and hence these women become bitter with men because they were unable to land the guy they loved. I've seen this story repeat so many times in front of my eyes, its like clockwork. And high expectations for two reasons. First, because they were able to have so many sexual partners they think guys will line up to be their beloved. Second, the alpha male they were with previously was better in some aspects and they will want the same in future partners.
Ultimately all this makes for a dysfunctional society when it comes to this aspect of life, and it is clear to see this if you are from a non-western culture and you live here.