i don't know about this. most people hate ads...
Hating ads is like an American pastime -- and I'm sure, people being people, they aren't all that popular throughout the first world. But when the iTunes Store video launched I thought the stupidest thing in the world was taking the ads out of the TV programs. I think the problem was, video downloads of TV were an unproven quantity, therefore the networks couldn't get advertisers to pay extra for ads in the downloadable versions and they couldn't get other advertisers, or they didn't discount steeply enough, to place ads in them. So they just yanked out the ads, no pay no play. Dumb, dumb, dumb.
We may hate ads. I can't think of the last time I know I bought something because of an ad -- it was probably for one of the kids based on their requests. I'm not susceptible. My toddler son was, very much for a while, but when after some time he got the idea we don't usually buy for me what I point out on the TV ads, he's become less susceptible. But the point is either a lot of people are quite susceptible or advertisers believe they are. (Man, they work the kids on the children's networks, let me tell you. It's a good thing our toddler prefers movies on DVD to TV for video recreation.)
All that being said, ads are an excellent source of revenue that may decrease consumer convenience but well holds down consumer pricing. I think NBC's crazy wholesale price hike was a put-up a job, so they could not renew in order to do their own restrictive rental-based service without having to take the heat for their content no longer being available to iPod owners, which is a pretty big number in the downloadable media arena (the copyright enforcement argument was garbage as Apple has pretty well managed to tighten up FairPlay so certainly there's no quick, easy way to strip DRM from iTunes music; and I've never heard of a good FairPlay stripper for iTunes video; everything I've read indicates iTunes has *reduced* piracy as many "free" downloaders will choose to pay iTunes for an official license rather than download for free).
But in general advertising could help with a lot of these price point arguments. Most people will take pay+ads over not having access to the content for iPods at all, especially over this "expires in 72 hours" mess. The only thing NBC could be after in this is you miss a show, don't record, you pay for a time-limited viewing, then if you're a fan you buy the overpriced DVD version at the end of the year. If you buy through iTunes, you already have the season at the end of the year, no need to buy their outrageously priced DVDs -- the productions costs of which mind you have already been paid for and profit taken from advertising during the season.
I'm all for dealing with ads if it means more content choice available to consumers. You don't have to buy the ad-supported material if it bothers you that much.
iTunes has given TV networks the opportunity to make money an extra time for their content, and if allowing ads gives them yet another extra time and keeps providing the content, then I can deal with it. Not everyone will run ads. iTunes Store music labels want DRM, but look at EMI: not all labels insist on DRM, and that extra $.29 per track is and it isn't, as the album price has remained the same.