My only issue with this was the steel potentially rusting over 1000 years. There is a lot of water vapor that moves in and out of a house and mitigation of that water is important. Stainless steel will rust given enough time/water too.
Anti-corrosion coating on the steel and waterproofing of the foundation slab with a self adhered membrane are two overlooked points imo. Easy enough to tie in waterproofing of the slab with a water/vapor barrier on the walls and the roofing underlayments too.
Unsealed brick is also relatively weak if there is a significant amount of water vapor and prolonged years of freeze/thaw will eat away at the brick/mortar and reduce structural integrity of the facade.
I may be biased since waterproofing product development is my day job.
As for the other comments on the cost of steel being obscene, I'd counter that volumetric steel modular construction is a growing market. Steel is also more easily recycled than wood and lumber costs in 2021 were really high. Probably part of the reason Katerra went bankrupt too (mismanagement played a role too I'm sure).
I agree on the steel in the ground with corrosion, I'm guessing the author implies there is an anti-corrosion coating on there already (since not having one seems idiotic), but I suspect it wouldn't last that long and honestly it seems a little excessive since slab on grade is pretty common and I've seen 200+ year old homes sitting on big rocks that are sitting on compacted soil.
Fun article though.