In addition to that, there might be an effect due to the media hype around investments of Warren Buffet. People see in the news that Buffet invested in companyXYZ so they think that must be a smart idea and also invest in the same company and therefore driving the price higher...

Does that change my thesis at all?

I was just drawing the distinction between beating the market through passive investing (simple stock picking) vs. what Warren Buffet does.