This is a common Star Trek Trope in not just the movies but in the TV series as well
I'm sorry I have to disagree but there was not one TOS episode where the
Enterprise was ever near 23rd Century Earth.
It sometimes was the only starship in the vicinity of another one (e.g. "The Immunity Syndrome").
Bob
I think that's what he meant, that TOS often had
Enterprise be the only ship in the sector/quadrant. It makes sense that the Enterprise could be the only ship in the quadrant during TOS. Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space. In a given sector of space, especially out toward the edge of the Federation, it stands to reason there will only be one starship in the area. In contrast, the closer one gets to more heavily populated areas of the Federation, we should see more ships. One would think that Earth, the capitol of the Federation, would have a couple of shipyards and a whole bunch of ships floating around.
Compare it with the navies on Earth. There may be only 1 US ship at some particular spot in the ocean, but there are a whole bunch of ships docked at Washington Navy Yard.
On the other hand, maybe they expect the planetary defenses to be enough.