> We wouldn't be able to prove if Google ranked sites with their ads higher

This to me is a different argument, though admittedly reasonable to arrive at through the language of "paying Google for placement".

> I think it is a better assumption to make, that Google puts their profit above luser experience, when it comes to search ranking.

I mean, yes. Though I should hope I needn't preamble any statement about <company> with how cynical I am about their intentions... It's not relevant here because I'm not arguing on the grounds that 'Google would be ethical and kawaii if they didn't accept payment for organic search ranking'--I'm saying that from a business standpoint it wouldn't make sense.