To be honest, I haven't seen advertising on the internet in literally years, and I don't think I'm the only person to block ads when they browse.
I'm not sure that I would agree that only the most commercial things have ever been ad supported - I think there was a 'golden age' of ads when people watched broadcast TV and could not skip the ads, but that train has truly sailed at this point.
There was certainly enthusiasm for internet ads, and you certainly still see them, but the initial enthusiasm for that is being radically readjusted as advertisers realize just how ineffective internet ads are in the main. Partly because people interact with content differently, and partly because most content that is time-shifted (DVRed or torrented or whatever else) doesn't even have ads.
Hulu and other streaming models are an interesting phenomenon, and it will be interesting to see how that plays out, but magazines and newspapers are, for the most part, finding that online ad based models are not paying their bills - the New York Times online moved back to a subscription model after not being able to make ads work.
I think the reason that advertisers are not willing to put money behind online ads is not because the are unwilling to try it, but that they have tried it and know that it doesn't work.
Ads have a future in reality TV shows and sports broadcasts, but not in quality programming, which is going to be paid for in the future by some kind of direct payment, whether it is after the fact subscription or before the fact sponsorship through kickstarter or something else. Netflix sponsoring some original content is not quite the democratization that we all hoped for, but it's a step in that direction. Smaller funders making more niche programming and recouping their costs in more creative ways (largely ad free) is the future.