I know a person who fine-tuned stable diffusion, and he said it took 2 weeks of 8xA100 80 GB training time, costing him somewhere between $500-$700 (he got a pretty big discount, too, at today's prices for peer GPU rental it would be over $1,000).

Sure, it's peanuts compared to what it must have cost to train stable diffusion from scratch. However, I think most normal people would not consider spending $500 to fine-tune one of these.

Edit: Though I do agree that once this kind of filtering is in place during training, NSFW models will begin to pop up all over the place.