Very easy to do a shamble in the eyes of fans, very hard to attract other people who didnt play the games.
Myself and my SO are both under 35. Most of our friends like the show, and they range from 26-41. I know one of my best friends, who's cousins kids watched the show intently, all between 16-20, as he told me.
It was also a weekly discussion point in our friend groups, it was fairly actively engaged.
It was also a gangbuster for ratings[0] and is number 6 on the Nielsen streaming stats[1] with a staggering 837 Million Minutes watched in a fairly short period of time. Willing to bet you don't really "get there" without a healthy amount of people under 35 watching this show.
[0]: https://gizmodo.com/last-of-us-finale-hbo-max-pedro-pascal-h...
[1]: https://variety.com/2023/tv/news/the-last-of-us-nielsen-stre...