edit, let me ask, are you saying that transaction fees are not required if oyu want to cash out of BTC right after receiving a payment, and you wish to do this 100s of times a day?
I think you do.
Ah, I see you're talking about external fees, on exchanges and so on? Yes, of course these are variable. Currently I pay 0% on britcoin, but it's a bit inconvenient.
As bitcoin matures these external fees would be another incentive for merchants to use bitcoins to purchase supplies.