Well, its hard to say no one ever really figured, at least in trek terms, that Pluto=end of Sol system. I always figured the call came from outside the system, and the only one in range line, comes from what some said from above, "we're the only ones who can get there right now/in mere seconds" anyone else would have to come from another system, or power up their engines, etc... I would figure they would have to have something within the systems, but as TNG's "Best of Both Worlds, Part II" showed, they looked to be sublight popshooters that were horribly out of date,
This, though I can agree, seems somewhat silly, but fits with TNGs line that active starships rarely come to Earth (which seems odd, considering it's the Fed capital). The worst offender has to be ENT though, considering the ships would be slow, warp one to three at best (possibly four, but warp one, three and five seemed to be the mile stones in the series).
This is why sometimes dramatic licenses suck, I mean I loved ENT, and the people involved did a great job (so any of you writers, creators, producers, etc... please don't think I am putting you down), but it's frustrating to see a fleet establish and then they don't use it. However, considering ENT and Generations isn't the first to do that, I'll let it go.