There's about 138,000 active subreddits. I don't believe that this industry is targetting even a majority of them.
You say "sudreddit". Marketing teams say "self-selecting target segment".
The first one sucks for a multitude of reasons, the second one you basically don't notice are ads, yet they're all over reddit.
Can't say I know how it looks everywhere on reddit, as I'm not everywhere on reddit, but the AI subreddits I referenced earlier are filled with it, and I've even received offers myself to get paid to pay about stuff and I'm a nobody, so surely I only know of the surface.