Some people say Ubuntu is finally a usable desktop OS for average Joe. Even if that's true, it took how many decades for free operating systems to reach that mark? They're at least 20 years behind in crossing the line (though perhaps now gaining ground rapidly).
The financial incentive enabled by proprietary software gives us things like Photoshop (sorry, GIMP still sucks) and Illustrator, Flash, Windows or OSX.
Certainly nobody would suggest that the open source community be legally prevented from making a Photoshop or Outlook or IE competitor. So why can't we have both and let the market decide? Why must proprietary be evil?