Probably the same reason kissing in public is OK, but fucking is not. "Sex sells" doesn't actually mean what it seems to mean.

I'm also wondering why super-targeted advertising (showing actually relevant, and deeper integrated ads for different pages/posts/videos/etc) is still not a thing, there was a movement towards it but it kind of died down, even as everyone is shouting about ML and AI everywhere.

Because they are scared it may hurt their brands.

And to be fair, most of the ads that appear near porn is extremely low quality, so they may be right.

Of course it is a self-perpetuating issue, but that doesn't mean that they can just fix it.

Subconscious is fine. It's overt porn they don't want.

The click through for non-porn ads besides porn is, in my experience, almost non-existant.

Wasn't there an experiment where a sandwich company bought ads next to videos on Pornhub to target hungry people who'd just gotten off and were hugely successful?

Found it: https://blog.eat24.com/how-to-advertise-on-a-porn-website/

Well if you find a sandwich company, you should let them know.

But Mattel, Sony, GM, Apple, and American Airlines aren't signing up anytime soon. That's the problem for Tumblr.

I think this is just one of those instances in which a customer just starts costing you too much money. Will banning the low-rent crowd make a difference at this point? Who can say really. But keeping them pretty much ensures you will not get access to the deep pocketed advertisers.

Mattel could advertise on all the weird Brony shit, Sony could sell their VR gear, Apple could advertise next to the masochists, American Airlines could advertise seat sales to the country of the ethnicity specific ones... you could make it work.