But a 0% fee pool may not be profitable if there are a very large member base.  How much you earn in a pool is a function of your hash rate percentage to the entire pool.  

There will still need to be new pools to open up to ensure that there are pools of varying hash rates and where members can find better yields even with higher pool fees.

And in the event the pool isn't profitable at zero percent, many of those members will simply stop logging in or leave the pool, thus slowly lowering the hash rate of the pool.

It's yet to be seen as the game expands, but I think there will be incentives for opening new pools or joint higher fee pools as we can go forward.

Perhaps going forward Pool can be private or password protected to allow collaboration and cooperation between like minded members.  In that way, perhaps you could have a pool owner open a pool, even with a 10% fee or so, but perhaps that fee would be justfied because it's a 'private pool'.  You know what I mean?