I edited my original post to make that clear, I thought "allowed by default" was sufficient but several people had the same reaction.

Though I expect you'll find that the number of adblock users who check such an opt-in-to-ads box to be vanishingly small.

The goal is to make the web a markedly less hostile place to visit by eliminating intrusive ads while still allowing sites to support themselves through advertising.

That's not my goal. My goal is to eliminate unsolicited advertising.

I don't want it, and if websites have to find other, non-advertising-based business models to support themselves, so be it.

If I'm installing an ad-blocker I want it to block all ads.

this is why most people use ads, they are annoying and intrusive.

That doesn't mean it should be enabled by default.