the Enterprise is typically deemed the Flagship of the Federation.
Only in fandom, though. On screen, the E-D was the only ship of that name to carry the moniker.
I figured it was important by virtue of it being first.
But if NX-01 made the name Enterprise
important, why did Starfleet not build any starships of that name for the next hundred years?
It seems that the name for Kirk's ship was picked more or less by random, perhaps mostly in honor of the WWII aircraft carrier (in the real world, the most "heroic" of the lot), at a time when Archer's voyages had already been forgotten - and it was Kirk's ship rather than Archer's that made the name Enterprise
a prominent one in Starfleet.
The UFP was in its infancy, so they wanted to downplay Earth to promote "unity". The name Enterprise was put on hold till things firmed up.*
*I'll take fan rationalizations for 1000, Alex.