Can you elaborate on why you think reddit is pushing out the weirdness? I don't think it's a zero sum game, you can have both normies and weirdos in entirely separate subreddits.
Yeah, but what's the point of hosting them? Like what do you sell on r/dragonsfuckingcars? (no, I'm not joking)
And what does the existence of such a place at all mean to a prospective advertiser? Imagine a viral picture of your ad next to one of those posts.
But okay, let's ignore porn. How about subreddits that deal with subjects like depression, gender issues, politics, etc? What do you sell to those? Maybe a book or two but probably not very much. And they're also ripe for "hilarious" ad/content mismatches.
It seems to me that from the advertising point of view, Reddit would be a lot more desirable to advertise on if it was nothing but endless cute cat pictures.
How did advertisers become such puritans? Playboy magazine carried ads for normal products just fine. Every newspaper deals with "depression, gender issues, politics" and they somehow survived trough most of their history on advertising revenue.
Surely there should be marketers that see "Imagine a viral picture of your ad next to one of those posts." and realize that everything apart from "Imagine a viral picture of your ad" is often irrelevant.
They don't need to monetize every sub. Most subscribers to dragonsfuckingcars probably sub to several other subs that can be monetized. Keeping all the weird niche stuff around keeps users scrolling longer. Just keep them off /r/all.
The people who create the content (the reason people put reddit at the end of google searches) also like dragonsfuckingcars, and if you push them out they stop writing about their vacuum cleaners and the content becomes the default subreddits which are pretty much entirely people yelling political talking points at each other.