Exactly. So lets talk about a different, important number. Watts per dollar per day. The only one your accountant/investor cares about. Its something like double or triple for space-based solar cells, if you can deploy them efficiently.
Both are VERY debatable points. capital outlay in $56 million per launch for Falcon 9. Is that more or less than buying up hundreds of square miles of urban land? Deployment/construction is also different, and perhaps very much cheaper, under zero-gravity.
As for efficiency losses, I don't know what figures you used but its essentially the same problem to receive photons on the ground from a maser in space as the original task of converting sunlight in the first place. Efficiencies there are in fact very high (re: OP).
