I can't say from experience because I don't wear diapers but I don't see how wearing and using diapers for too long could cause a loss of bladder control.
The reason I say this is babies wear diapers all the time and use them from birth up until 3 years old sometimes and the babies and toddlers using their diapers are able to be toilet trained and have bladder control.
However I could see how it could be possible to weaken your bladder from emptying your bladder right when you need to into the diaper and not thinking about it.
But even if you do weaken your bladder muscles somewhat I'm sure overtime you could do exercises to stretch and strengthen your bladder muscles again and regain complete control.