But if you want some examples, Michelangello produced some nice forms of art. How? By finding someone wanting to pay him for that. But, hey, maybe you don't think that example to be representative since Michelangello didn't produce music. So be it. J.S. Bach, maybe you heard about him, made a live out of composing and playing music. How was that possible? Well, by finding someone wanting to pay him for that. What would have happened if nobody wanted to pay Bach? He simply would have find another way to earn for a living. If distributing media is a bussiness no more, just find a different bussiness.
That doesn't really work today, though. Two problems:
First, Michelangello and Bach lived in an age where wealth was heavily concentrated in the nobility and the clergy, two groups who were very interested in commissioning artistic works. Nobody has that kind of wealth nowadays; Gates and the Waltons aren't nearly as wealthy, proportionately, as the wealthiest people back then.
Second, that only works for certain types of works. Do you know any billionaires who would commission new video games, comic books, or Hollywood blockbusters?
Intellectual property creates artificial scarcity, yes, but it also creates a viable market for information. The ability to control licensing means that rights-holders can force their audience to pay for the value of their content. This gives content producers a strong incentive to create value for their audience.
As simply as that. Really.
It's possible that a no-copyright commission-based model could work, if audiences/readers/players/etc felt obligated to tip the content producers generously for producing a work. But it's not nearly as simple as you suggest. I'm not totally convinced that it would be better than a copyright system. Certain works would be under-produced - especially high-budget works and works that people might enjoy, but feel ashamed to sponsor. Also, the amount of money going into content-production would almost certainly be less than now - most likely, what people are forced to pay under copyright is often more than what they would pay without compulsion.