Obviously there is no one easy explanation here (as you can see by all the different responses).
I think evolutionary factors play into a general affection people have for boobs. They are humans first source of food and with it an extremely intimate contact. Also on a “birth readiness” perspective Boobs on a woman suggest that she can feed a child (just as wide hips suggest she can bear one).
There is something to be said about culture. Since boobs are considered “sexual” they have to be covered in “decent” settings (see also discussions about female presenting nipples on social media) which simply adds to their sexualization.
Also, in my sexual experience (Bi male) nipples and breasts (boobs/man boobs …) are erogenous zones so playing with them (touching/pinching/kissing/biting…) actually is arousing thus they are “sexual” parts.
Thats just my two cents.
I’ve been using Linux exclusively for ~14 years now. Heavily gaming on Linux only for the last ~8 years.
It was possible (though sometimes headache inducing) to play most games back then (Wine and soon Proton to thank) the biggest change IMHO came with SteamPlay since it turned the headache into one click on most games (thanks to the amazing work of wine/proton developers and the tinkering of the community).
When the SteamDeck released people seemed surprised at the breadth of games that were running on day one. To me it was not really a surprise since I had been Linux gaming with SteamPlay all the time and was almost expecting games to “just work” (though I still would and still am checking ProtonDB before purchase).
What the SteamDeck changed in my view was
I feel that the SteamDeck with SteamOS has really put Linux, especially Linux gaming on the map. Even though I want to be like “Linux Gaming has been a thing forever, I was doing it before it was cool” ;) I have to recognize that fact. In the past years I’ve seen so many people setting up Linux especially by the way of SteamOS (using HoloISO, Chimera …) just to play/mess with it which is also why I think an Official SteamOS release will make a huge difference.
Tl;dr: Gaming on Linux was a thing before. But the SteamDeck/SteamOS 3 made a huge impact nonetheless.