I dug in a little more, and I think your Earth cooling estimate is high at $2.5–3.0B/​GW with water chillers. An NREL study was more like $0.7B/​GW with water chillers. Also, we may be able to dispense with the water chiller (as you have assumed in space), and then it could be even cheaper. So I doubt it’s actually going to be cheaper to cool in space. However, your point that cooling in space doesn’t wreck the economics still stands.
I dug in a little more, and I think your Earth cooling estimate is high at $2.5–3.0B/​GW with water chillers. An NREL study was more like $0.7B/​GW with water chillers. Also, we may be able to dispense with the water chiller (as you have assumed in space), and then it could be even cheaper. So I doubt it’s actually going to be cheaper to cool in space. However, your point that cooling in space doesn’t wreck the economics still stands.