Well, sure, but since Mastercard uses basically the same IT infrastructure nowadays to handle Maestro cards, almost all “official” Mastercard ATMs also work with Maestro cards. I think the number of supported ATMs Mastercard publishes on their website is almost the same.
Sure, Mastercards are a more flexibel tool for all kinds of situations and there is a reason why Mastercard advertises the relatively new Debit Mastercard as the modern debit card, but Maestro cards are far from being useless.
Don’t forget how this tread started. Is it worth to get a Maestro card if Mastercard is not available? I would argue yes. Because one can get cash in a lot of places all over the world.