in honor of the ship and crew saving Earth twice in 15 years...
That makes since.
I don't know much about the Enterprise B besides it being a modified Excelsior-class but it's advancement may have been planned to be the best at what it does of it's time deeming it worthy of calling it Enterprise. The same with the heavy cruiser, Ambassador-class, war time ship that C was. The D was a flag ship that saved earth multiple times and the E was also the most advanced ship of it's time. Maybe the Enterprise label means it's the best they have?