All you would need (with a 1% fee) is people using the pool to earn 5 BTC total throughout the month. I don't think it's that big of an issue.
I don't think a pool can affort 0.05 BTC in a month with only 1% fee. Because pools can not earn 5 BTC total in a month and additionally, we can see some of pools want less than 1% fee.
I believe the fee is there to keep everyone and their mother from opening one. If it's cheap, everyone makes their own and there's no point in having them.
But we are talking about operation costs. It is paying months by months.
Everybody can not open a pool beacuse if you want to open a pool firstly, you have to buy at least 1000 ghs miner and also you have to pay the openin pool cost.