Oh, I'd completely agree that Enterprise is the best-known ship, but isn't it sort of begging the question to say that it's therefore necessary for Jane Q. Publica? Those aren't the same thing. Similarly, Juan Que Publico most certainly knows the names Picard and especially Kirk, but that's a vastly different proposition from actually needing them to be in a show in order to watch it.
It's all about familiarity and what aspects can most
people relate to. This is true not just for Star Trek, but for anything. In the case of Trek, the Enterprise
is a familiar household name that more people than not instantly associate with Star Trek, regardless of what else changes.
It's easier to move away from the Enterprise
once a new era has been established for awhile as it was the case with DS9 and VOY both being spinoffs of TNG.