Why?  As I said, if a poker site is only attracting freerollers, they will never make any money.  For a site to survive, let alone thrive, they need to attract real money players who are willing to deposit and spend time playing games that the site can rake.  If the site is, at best, raking their own money back they will shutter in months.  It's happened time after time after time. 

When a site is only catering to freerollers, what do you think happens when people who are willing to deposit come in and take a look around?  They see the bad software (which 95% of the users don't care about because they are playing for fun), they see nobody playing for anything other than freeroll stakes, and they leave.  There isn't even an incentive for them to stick around and try to game start because all of the marketing capital is spent running freerolls.