The thing is, all the Enterprises were in nearly a class of their own. It's like the name Enterprise referred to the vehicle itself. It is also true that the vessels were made from the general ideas from the previous generation, and upgraded to meet the standards of the current generation. The mission was almost always the same.
If the Collossus was destroyed, it wouldnt be a big deal if a next generation super destroyer were created with the same name, design, and mission. However, if something like the Psamtik (sp?) were destroyed, and it was just one of a large handful of Vasudan destroyers of it's kind, it would be kind of taboo to name one of the next generation destroyers Psamtik, unless it was known for having the same one-of-a-kind crew and/or mission. Thats how I see it
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