It would take far more energy to extract the 3He from the moon's crust than you could get fusing it.

The moon is high in silicon. You can make solar panels from mostly moon dust. Then build solar panels in orbit which are 4x the power generation of sea level panels and they experience less shading.

True enough. But by the time that could be fielded, our energy problems will already have been solved, or civilization will have collapsed.

I agree with you relating to our existing energy problems. However I expect that humanity will be attempting to use as much energy as it can possibly create for at least the next 1,000 years.

I hope we have a bright future growing into space, creating a Dyson ring, orbital habitats, etc.

Replacing our current use of fossil fuels has plenty of strong ground-alternatives. I like the idea of Thorium salt reactors for base load, hydro stored energy and lots of local wind and solar.