I generally agree with what you are saying. But if you look at /created, I think you'll see that even a trivial level of prevention, like a reputation bar, would stop a rather high percentage of this junk. They're abusing for pennies in most cases, not dollars.

The time required to sock-puppet more accounts isn't a high enough bar at the moment, but it would be if they needed even 30-40 rep to post using the NSFW tag. I don't see why a hard fork couldn't include a restriction like that, hypothetically.