It's not really generational; people have always hated advertising. They hated it in the newspapers, on buildings, on TV, before movies, inside of movies, in magazines.

I don't really see advertising in general going away short of legislation preventing it; that doesn't mean that online advertising will always be as profitable as it is now, but there's a question of "where else will people advertise?" People advertise where people are; online advertising will lose its value when people spend time elsewhere.