I think bitcoin atms have many headwinds. As already mentioned, they must charge a large markup, so will not be competitive on price. But also I am seeing more and more wallets that incorporate some sort of marketplace. Why would someone drive to an atm when they can buy right from their wallet on their phone? Maybe there are some reasons, but in general I see exchanges more used by traders and institutions, and wallets more for small time retail. This is maybe a simple way of looking at it, but I'm a simpleton anyways.