I'm not so certain. I used to buy a broadsheet newspaper, which was full of ads. Now I pay a few hundred a year, and get the same newspaper online, with no ads at all.

So, the precursor to online media has already gone through this paradigm shift.

I mean, what you're saying is "If I pay for a product ads go away"

Which is partially true, but it only shifts the distribution of the problem. Once your service gains enough popularity network effects cause it to gain value. You have to worry about high priced buyouts of the entire service (great for the site owner, terrible for the users).