You're suggesting that we should magnetically levitate the launch vehicle in free air above a track running along the ground? That seems like it makes the problem a lot harder — instead of having to push it through just the air between here and space, which is about ten tonnes per cross-sectional square meter, you're pushing it through another two or three hundred kilometers of air, which is about another 200 tonnes of air per square meter. You know that shroud of plasma surrounding a re-entering spacecraft? That's the power required to push an orbital-speed object through air — but in that case without even maintaining velocity, let alone rapidly accelerating, and in that case it's the rarefied air of the stratosphere. You're proposing to do that for the majority of the track. That seems like a bad idea.

Yes, generation costs will likely drop significantly below US$0.04/kWh eventually. But that's a Kardashev-Type-1 kind of event. Generating the power on-track may not turn out to be less expensive than long-distance transmission, because it depends on things like sunlight availability. Of the few suitable sites, most are pretty cloudy on one side.

No moon or planet alignments significantly reduce the energy barrier to get to orbit.