People definitely like teepees and yurts (and thatched roofs, dry stone walls, log cabins, etc.), it's just that at some point the practicality gap becomes too wide to contemplate.

But this is a reasonable point to raise. Although both would serve their purpose a concrete viaduct is much cheaper to build than a masonry one, to the point that it may be difficult to justify the latter no matter how strong the public preference is for it.

Not to mention their comparison, modernist architecture, is just mid-century. There is post-modern architecture after that and arguably also contemporary architecture further after that (however vaguely defined).