Bitcoin ATM isn't that easy to build as a business. You need to conduct a study on how many bitcoin/crypto users are around your area where you'll be placing your machine. Without knowing this kind of stuff you're not to fit to stand a bitcoin ATM machine not until you gather enough information that your business may bloom. It doesn't work like there's only few machines out there If I place one I can profit.
I realize it's not easy trying to build a business like this, but given the fact that a lot of crypto buyers don't want people to know they're buying crypto, surveying potential users isn't a cut-and-dry thing. And I've read news articles stating that some people who are buying crypto haven't even told their significant other that they're buying crypto...so what makes me think they'd tell a total stranger whose motives they don't know whether they have crypto or not?
I've talked to people in the two stores locally with Bitcoin ATMs (a vape shop and a 24-hour convenience store), and they have told me they get a small but steady stream of people using the ATMs.