The problem with your idea is that Google likely makes waaaaaay more money selling a single banner on YouTube's homepage then they would make in a month or more

The problem with your idea is that Google likely makes waaaaaay more money selling a single banner on YouTube's homepage then they would make in a month or more of thumb-up micro transactions. A simple banner at the top of Youtube can cost hundreds of thousands of dollars, and we're not even talking about the fancy stuff you sometimes see on YouTube. Until that bubble bursts, I don't think you're going to see ads go away on large sites like YouTube.