Eastern block panel building settlements were built from per-fabricated segments mass produced in a factory. Then assembled on site from these segments by cranes rolling on rails.

https://en.wikipedia.org/wiki/Panel%C3%A1k

You can actually tell quite easily in many cases where the crane rails were & that their most efficient location was the factor, not stuff like ergonomy or aesthetics.

The end result was indeed a lot of housing capacity built at record time. On the other hand the quality of the flats was often disputable and the new high density neighborhoods often lacked basic public amenities, at least initially.

In a more modern context there are also issues with lack of parking space (no one expected so many cars back then) and lack of thermal isolation (usually fixed by replacing the windows by modern ones & isolating the sides).

>hyper-efficient "fog" showers. ( Legend has it that the project was spiked because it would put too many electricians and carpenters and so on out of business. )

Modern Japanese showers are pretty much like that. Japanese toilets are also much much more water efficient than what you can see here in Europe, not to mention mostly including bidets and other civilized living amenities still mostly considered extraodrinary around here.