Good exchanges won't make much.
Rogue exchanges and wallet services (which mostly steal) will make tons of money. Even dickhead Mark Karpeles had 500mil USD
This is the shit. Bitcoin is the new shit in making money out of thin air.
Coinbase does 50k in transactions a day (what I made up from briefly looking at graph
https://coinbase.com/charts. They hit you when you buy and sell.
What is an average transaction? One BTC - $225000 a day at $450 1 percent? $10 average transaction (highly unlikely) $5000? Then again that 50k is transactions, not buy/sell, but i'd imagine at least half are for buying and selling, as why else would you use coinbase?
I don't know what these exchanges cost to run, but from what I can see opening a legit exchange like coinbase seems to make huge profits, and they deserve to as they are the only legitimate usd exchange in my eyes, so they can get away with 1 percent premium and even more if they really wanted to fuck us.
There is tons of money being made, and to not think so is naive.