I think it would be difficult to enforce that rule in any official capacity, and would carry its own share
of issues. Fans being shareholders means that fans have the ability to direct the company, which could easily result in fans making corporate decisions as to where the art should go. That is a crapshoot that can go very well or very poorly
. It's also worth noting that a very small percentage of people have the kind of money to buy a significant number of shares which, coupled with the small percentage of fans that would be passionate enough to buy stock in the company, means that the future of a corporation can end up placed on the shoulders of just a select few wealthy, passionate fans.
Really, I think this is better as a social rule than anything else, and I mean that on both sides. If you're going to spend huge amount of money investing in the future of a company, get invested in what that company actually does. If what the company does is art, pay attention to the art. Don't just throw money at it and walk away, feeling safe in your future financial success; make an effort to become educated in whatever it is that company is involved in doing. Whether it's television, soda, bottle rockets, whatever the company does, if you don't care about the product, then why are you here?
The same goes for the fans. If this is something you're passionate about, make an effort to get involved. That doesn't just mean becoming a shareholder; try to get a job at the company, and make your own art. If you love fantasy space operas, then get into college and look into making more fantasy space operas. If you love Mass Effect, specifically, and want to see more Mass Effect, then invest in Mass Effect's future by becoming a shareholder for the company and always, ALWAYS purchase the products you love and wish to see more of, because the fact is that piracy hurts everyone.