Because people do not donate, even to stuff they love and use a lot. For a company to block those legitimate ads and then put their own, while pretending they are helping website owners - that's a scam. And nobody would swallow it unless it came with the promise of sharing some scam money with the users.

I'm for a free speech internet where users pay a cheap and fair price to creators for content, that's a much better model than ads – and it is probably the future for any quality content.

In general, HN users can be trusted to take the side of corporations over humans in the vast majority of situations.

EDIT: Downvoting without giving reasoning just lends further credence to my point that their views are based in selfishness rather than reasoning. ;)