...And lest the obvious be forgotten (I'm fairly good at stating that), there's the possibility that nobody thought the name Enterprise
would be worth lobbying for, and without lobbying, the name never came up at random.
Starfleet just doesn't seem all that obsessed with having a ship named Enterprise
at all times. There's the nil-A-B "lineage", which might have everything to do with Kirk's reputation and none with standard Starfleet naming practices, but we don't know of the name being continuously carried from B to C, and we know it was not carried from C to D - there was a gap of two decades. The D-E "lineage" again seems to be a Picard thing...
was a famous ship as well, according to LaForge (he read about her in the Academy), but we never heard of Starfleet using that name again after the 2354 loss of that vessel.