I need to watch that Voyager episode, I haven't seen it yet.Not necessarily. Don't forget that the Earth has essentially been cut off from most of the greater galaxy for well over a century by this point, and that without the vitality of input from other Federation species, their opportunity for technological advancement would be greatly diminished (if not outright regressive) if they've been in retreat over the past 100 or so years.
Remember also that "The Burn" occurred very shortly after Captain Braxton's era (as depicted onscreen on VOY), and much of the technology glimpsed in this latest episode seems even more advanced than that era's own tech, so I had no problem buying a state of scientific inertia as having set in since the UFP's near-collapse, but with some of the tech still being just slightly ahead of the U.S.S. Relativity's.
Question, what was the time period the temporal agent showed Archer in Enterprise, with the battle being fought against the Sphere Builders in the future? I think he gets a Zindi religious icon from that time period in that scene? Or maybe that was a different flash.
Also, when we saw stuff scrolling in the future DB that Archer could pull up, what was the maximum century/year mentioned?