Lion? If you’re a human in 40k you’re more likely to be a mangy street cat forced to work in a factory processing other cats into fancy feast. Fuck yeah I’ll be the Taus little pet over that, I can work in at a space turnip farm or something, maybe they’ll give me little human treats.
While everyone’s bringing up good points about the videogames and YouTube videos, the biggest reason is that the public opinion on “nerd culture” finally fully flipped some time in the early 2010’s, after the Star Wars and LotR movies started moving the needle in the 00’s. All the nerd “final bosses” of the 80’s and 90’s were turning out to actually be quite good, or at least fun, so audiences were more willing to engage with things that had previously been socially off-limits, like Anime, D&D, and Warhammer. Between them being made more accessible for the new audiences and the stigma fading away all the old nerd hobbies are becoming mainstream.