According to little write-ups on the boxes of some Star Trek toys I have this is pretty much what happens. They keep building ships and when an Enterprise gets destroyed they assign the name to the best ship they were working on next. I think that's how the Enterprise E was rolled out so fast, it was already in development when the D happened to be destroyed and it got called Enterprise. And another constitution class ship that happened to exist became named the Enterprise A, although in that case probably for sentimental reasons to keep Kirk's Enterprise as the same type of ship it had always been - because by then the Excelsior class ship was around and those were supposedly more advanced. And sure enough the Enterprise B was Excelsior class.
Enterprise A wasn't destroyed as far as I know, just decommissioned eventually. Dunno 'bout B. I think the C is destroyed in a time-travel episode of TNG. The D is obviously destroyed on screen in Star Trek Generations.