sadly, most of the time if theres nothing for them to grab onto, they get stuck on their backs. thye don't have the capacity like some other snails to flip themselves right-side-up
I have three in there that I acquired when I bought the tank from my gf. They are little busy bodies and fun to watch. I have noticed that the smaller margarita snails tend to hitchhike on their large cone shaped shells. Why they do that, I don't know. Free ride? Cleaning stuff off their shells? (their shells are actually covered in coralline and little hard white tube worms). I have noticed that these hitchhikers sometimes make the turbos topple over and that the Turbos actually lift their bodied up and make quick sharp turning movements to try to shake them off.
In short, yes I do think they would eventually die if you don't flip them over, they are just too big and heavy to do it themselves. I know I have 3 and they are easy to spot in my 34g so I scan the tank for them every day and make sure no one is upside down