I share your concern about putting too much in orbit. The rest is FUD.
Terrestrial solar cannot provide 100% of the electricity. What we are talking about here is continuous base load power. The only options today are nuclear or burning fossil fuels. That is what we need to compare this to.
It is theoretically possible to generate enough terrestrial solar and to store it in batteries to provide power continuously to the grid. What would such a system look like that could provide all the energy needs for a country like the UK? Consider, there can be entire months of total cloud cover in the winter. And even the clearest months are overcast half the time. And, you know, the night.
https://weatherspark.com/y/147871/Average-Weather-at-London-Weather-Centre-United-Kingdom-Year-Round
How are we transmitting that power to where it is needed? Any losses there?
The square law is a thing but we all know there is a difference between a laser and a flashlight. And the collector will clearly be bigger than the transmitter. With advanced beam forming, microwave transmission can be very efficient. And it can be sent to wherever you need it. No other transmission losses.
As for cost, if NASA two years ago thought it would cost 61 cents per kWh, I am quite optimistic. There are many, many ways this cost will come down over time. Look at the reductions and improvements in solar overall. The input cost (the sun) is free. So we are talking about process engineering. We are good at that. But even this worst case number does not need to drop by much we we do proper accounting.
Again, the comparison here is to other alternatives for baseload power. And nobody is trying to build space solar at scale this year. This does not have to replace terrestrial solar. We should do that too, as much as we can. What we are talking about here is being able to turn off the coal plants. You don’t want that?