It wasn't just the big guys. I had a smallish website that I started in the early 90's. Ten years later it was seeing 300-400,000 monthly visitors. I was doing it all for free because, like the big guys, it gave me consulting customers,.
Then Adsense arrived. Why not, I thought. The first month I pulled $1,500 which was a good pile in 2003!
Who throws away free extra money? Not this guy!