if we take somewhere like kraken, the average of the maker/taker fee is 0.2% if we're making a rough estimate. they did 25,000 btc in volume today. that's 50 btc in fees, so 5 btc a day to put away. that don't feel like a lot to me but I guess it adds up over time.
sure, they make much more in fees with margin and dark pools and stuff but maybe we'd be surprised how modest their earnings are. whatever happens people need better than what's going on now.
ah no they go to 0.3 a day so they would put away 25BTC a day, which would be near 10K BTC a year. When they have enough funds to cover their entire BTC holdings they no longer use fee. Eg it would take 10 years or so, and they would hold 100K btc.
