I think the best way to interpret this is to always ask whether there is something fundamentally limiting or constrained about a given issue, because if not, the broader assertion is that when the relative cost of energy and computation go towards zero, anything that is amenable to solution via application of those factors becomes on a long enough time scale just an engineering problem. A simple matter of engineering as they say.

Eg the question of being on or off grid presupposes that there is a grid in the sense we mean it today and more importantly that it is a fundamental determinant of what is plausible.

The thrust of this idea about robot built houses is undoubtedly not just that grid connection will be a trivial and well solved problem, but that it may be a red herring because it may not be necessary in the sense it is today.

With enough energy, you can pull water out of the air; and with the right energy and tech you can dispense with gray water and wastewater.

That's probably the far down the line extreme but the theory is the same for incremental improvements.

There is a world in which the limits we have are the limits of physics.

I don't expect to see it and don't have a great deal of faith anyone will, given current obstacles, but I think it's a lot less far fetched and a lot more plausible than we would have thought conceivable only a couple decades ago.