The bet that they are making is that, in the near-future, energy on Earth will be such an issue (especially if you want to scale) that DCs on Earth will cost more than components + launch costs
Why would energy be an issue? The Sun is shining, wind is blowing, the ocean has waves, nuclear is nuclear. All of these will just get more efficient in using the same constant resource.
Why would energy be an issue? The Sun is shining, wind is blowing, the ocean has waves, nuclear is nuclear. All of these will just get more efficient in using the same constant resource.