I messed up formatting in my other post.
I'd imagine there is no situation that guarantees the same quantity/quality of works are available, but I don't think the situation would be that detrimental. Expensive stuff becomes riskier, and if anything it pushes companies to reduce the cost of production (whether producers are paid less, or less work goes into post-production), and although quality will surely dip at first, the most profit will be found by getting the most bang for your buck.
The cost of making an album really isn't high. You can get equipment for a few thousand dollars. That leaves distribution/marketing. Outside of the internet, there's no reason why the role of the RIAA can't simply be to provide publishing for a cut of revenue of those physical CDs, as opposed to actually owning the songs and creating 200-page contracts that stipulate those three services. This would eliminate the whole "we sign a band to perform songs written by this random guy" scenario for royalties. The revenues are split between label (or whoever) and band, who each divvy everything up as needed. A band that really wants radio play will manage to get their songs on the radio, and it will probably revert back to radios getting paid to play content.
Beyond that, copyright was never intended to allow a person (or estate or whatever) to profit indefinitely from a work they created, since they are supposedly creating more works to profit from. A song written 30 years ago shouldn't be copyrighted, although a cover of that song performed last year should. A performance of that song from 30 years ago shouldn't be copyright-able either.
The Beatles aren't creating any more art...why should whoever owns their copyrights get paid because their likeness and songs are in Band Hero? It would be like trying to demand payments for using a performance of Beethoven's 9th from 50 years ago. There was a limit set so that after x years, society could use that "stuff" in more creative ways.