Rake and poker sites profit margins.

The rake on most sites is around 5-6%.
There seems to be little competition to lower rake.
Does anybody know how low they could go and remain pofitable, ie how much of the rake goes in taxes and operating costs ?

Games like StarCraft 2, Dota, etc. can take a 60$ lump sum from players once, or even no cost at all, and offer online play indefinitely. So the operating cost can't be the main thing. Must be taxes/security stuff for deposits.

It's a really good question though.

Theoretically we should get super low rake crypto poke sites (security fully automated, probably no taxes), but in reality, phenom can barely have two active tables last I checked.