There is a push, in some circles, for blanket licensing of digital music. Essentially, you would pay a small fee, and in exchange have the right to download as much music as you want. I have seen several of the most respected people in the "free culture" community, most recently Richard Stallman, endorse this approach, which is a shame. Not only is it a poorly-thought-out idea, but it would be far worse in many ways than the current system.
First, a necessary distinction - there are both voluntary and involuntary blanket licensing schemes being proposed, both idiotic. In a voluntary system, there would be a few groups that would collect payment in exchange for the right to download music, and consumers would choose one, and everything would be happy until some rightsholder gets upset for some reason, and denies one service rights to their IP, and then all hell breaks loose because this system only makes sense if every service has rights to every song. Can you imagine the confusion that would result if some services only had rights to some songs, and the set of songs they had access to wasn't even constant? Involuntary blanket schemes have the same problems, but with the added downside that everybody, even people that don't like music, has to pay for it.
But, a music tax? That's kind of crazy, isn't it? Surely nobody would ever suggest doing something like that?
Here is a more troublesome problem. In a modern, decentralized filesharing network, it's impossible to accurately track what files are being downloaded. (BitTorrent is a notable exception here, but only because it was explicitly designed for such tracking.) However, it's the job of the organization collecting the money to distribute it to artists based on popularity. Since popularity can't be accurately tracked, how are they going to decide who gets what? Since it's not really possible to do it in a fair and transparent way, what recourse will artists have if they believe they're being cheated? And then, worse yet, you end up with a situation where fans can artificially inflate the measured popularity of their favorite bands at no cost to themselves. Gaming the system would become an arms race, and eventually the measured download counts would have little to no bearing on reality. Furthermore, let's not forget that by centralizing, we've introduced a single point of failure. Any corrupt accountant could throw piles of money to whichever artists they happened to like, and no one would be the wiser. The fact is that it is completely impossible on multiple levels to ensure that the collected money will be distributed fairly to the artists.
Blanket licensing would also end up being far more monopolistic than the current system, which is actually a pretty impressive feat. Consider the plight of somebody trying to start a new collection organization. In order to be taken seriously, you'd need to acquire rights to every song available from other organizations; if the existing organizations have made deals which lock out newcomers (and they will, short of legislation to the contrary) then you're stuck. Only licensing some content won't cut it - if you have to give people a list of songs they can't legally download with your service, they'll just go elsewhere.
This would also be a death sentence for independent artists. An artist looking to strike out on their own would be in a difficult situation - everybody expects music to be free, so nobody would actually be willing to pay them. They would be forced to sign up with a label, which could then pay them next to nothing, since that's better than the nothing they would get on their own.
And then, this is just for music. Further on down the road, are we going to have another monthly fee for movie downloads? ebook downloads? software? accessing web pages that were previously free? Where does it end? And this is assuming that entire industries would be able to unite under a single banner; almost certainly, this is a ridiculously optimistic assumption.
At some point we, as a society, are going to have to come to terms with the fact that anything that can be represented as binary - all information, in other words - will be available for free to everybody on the Internet. We can hem and haw and decry the whole state of affairs, we can theorize about ridiculous payment schemes to assuage our own guilty consciences ("it's okay as long as somebody's getting paid!"), but at the end of the day, there's something we need to accept. The solution cannot possibly involve the current system of copyright, which is now so far out of touch with the way the world actually works that, were it suggested anew today, it would be regarded as a joke. Instead of molding society to the law, we need to find a system that actually works, and remake the law to match that.