Re: If YouTube is anything to go by ...
The problem you're talking about isn't charging, it's curation of content. And it's emerged because the cost of presentation has disappeared.
The real fumble, IMO, was trying to bolt paid-for content onto an existing "free" user-generated content site like Youtube.
The smart thing to do, IMO, would be to have a Commercial and a Classic/Free/Community section on YouTube, where access is restricted to content owners who have decided that they're charging for content. Nothing to stop VEVO or whoever else from making their music videos available on the Classic/Free/Community section if they want, but the key to a good experience with paid-for material is an effective search.
This is the same problem Netflix and eMusic both have - I really like both services, but their search is crap. Aside from anything else, Netflix has a horrible way of handling searches for material that's not available. I don't give a donkey's bollock what someone else watched when they found, as I just have, that the film I want to see isn't on the service. What I want is more likely to be a mechanism to say "I'd like to watch this, please bring it back" and for that mechanism to be one of the factors considered when negotiating for licence renewals or prpvisions. And as for eMusic, well put it this way - a lot of the time I use Google to find their page for the artist or album I'm after, because it's less of a bollockache. And that's desperately bad. (Also, they have a built in RSS service but don't offer you a "follow this artist and get updates when new content becomes available option" within their webservice, which is just arse-backwards).
Anyway, yes, curation (or its absence) is the problem that most content providers are having now that user-generated content is a factor. And it's no good simply getting rid of USC either, in some cases it's better than the commercial stuff (eg The Tunnel remains a better horror film than anything released by a Hollywood film studio in the last decade).