I tend to go to a forex company if I have to exchange before traveling, never do online banking for it.

I am not sure how the kiosk fx companies does it but moving money around is always a risk. They can probably charge as much as they like but it is that they cannot exchange unlimited amounts, you have to show how you got the money when exchanging above certain amounts. Money laundering regulations makes up a lot of the regulations in that area.

Bitcoin fluctuates wildly though, and exchanging it is hardly quick for the most part. Both brings down the attractiveness for consumer-type fx.

Airports are location monopolies so companies that operate at them have no incentive to provide cheaper services. They can operate at a healthy (for them) margin and the customers will still come. There is a reason those airport sandwiches are expensive!