Just because some Bitcoin ATMs use another exchange to set up the rate doesn't mean that it's worse for us as customers. At least that's what my experience was from the ATMs I used so far. 2nd part is true tho, BATM fees are generally higher than some other ways of buying/selling bitcoin, but I don't think that majority of them are in a lot of profit due that. Keep in mind that expenses one BATM owner has are not negligible; from paying the machine itself (which is usually in ~$10k area) and renting the place to paying all the taxes etc and you realize why fees are so high.
I've asked a while ago what's the tax for an atm/ PayPoint/ anything else in an inquiry for our major center, it costs 150 euros a month for one if you don't break the 1x1 space limits and the other 200 in utility costs, standard, no matter if you're running or not, that's around 12 euros a day, with a 5% you need 200 euros a day in buys/sell to pay for the daily expenses, some batms might be struggling to make that norm as for one I know in my chain store I've never seen a client around.
But for others, and I'm not going to name them but it's one without KYC and it's also in your country I've seen them running out of 10k euros for withdrawals in a day, and I'm already used to seeing the guys that nearly empties them each week early in the weekend when I go shopping
Same persons loitering for half an hour around, wads of cash pouring, I open the website to check the status, the batm has no money left !
Like you I also thought that they are making crazy amount of profit considering the fee, but then I actually met the guy who owns several of those (as I was a regular customer at one of his ATMs) that explained me the situation and that is far from the truth.
He doesn't have the right "clients".