Enterprise
When it came time to do the next Star Trek series, the creators decided that instead of going forward some more and try to come up with what came next, they'd go back and show everyone what came first. So they based this series around the first Starship Enterprise, back when Starfleet was first starting out and everyone was pretty much making things up as they went.
It's a nice idea, really, freeing them from a decade's worth of complicated continuity and getting back to the sorts of stories everyone loved in the beginning. The stories themselves, unfortunately, were a bit hit or miss. There were some rather pedestrian encounters with alien races, but no real investment in an overall theme or arc to the series until a couple years in.
My suspicion is that Enterprise hit the airwaves just about the time there was a shift in the way TV told stories. Battlestar Galactica, for example, started up in 2003, just a couple of years later. Enterprise, meanwhile, was closer to the early episodic Next Generation shows than the later, more complex Deep Space Nine.
At the end of the day, of course, it mostly comes down to whether a viewer "bonds" with a particular crew. For my point of view, Archer came across as a smug, pushy twit in charge of one of the most hapless bunch of space travelers I ever seen.
I freely admit that I might have drifted away before the show hit its stride - it took a while for the other Star Treks to ramp up as well - but while I took in the first season, later years found me watching something else.