By focusing only on $ per kW or $ per other unit, you seem to be ruling out consideration of $ per mission or $ per step, thus requiring $billions to be spent up front on technology that has only been proven in the laboratory. This is roughly as difficult as trying to kickstart a fusion reactor using nothing more than a matchbook.
Have you given any thought to demonstration missions, or realistic paths to funding that might eventually unlock enough money for the full system as you describe it? ("Government funding" not being a realistic path, given their demonstrated history with regard to projects that might actually give cheap power to the masses. This applies to any government large enough to fund this - such as US, EU, Russia, or China - though the exact means by which each one has demonstrated it wouldn't fund this, except to sabotage it and thereby waste the energy of those who might otherwise build this for real, varies by government.)
If not, why not? That's as much a part of the problem that needs solving here as the technology, and you've shown you can solve the technical side.