Eh....

Prefabs are a bit different.

What we call a prefab today is an outgrowth of a parallel development. See, during the 60's and 70's while builders were making split levels and ranches, mobile homes also emerged as a thing. Trailer parks.

By the 80's, the trailer park was dying out and the mobile home manufacturers decided they needed to innovate in order to survive. So they figured out how to build houses in halves, deliver them by truck, and then lift them onto poured foundations.

The houses of that 80's era are very easy to identify, they always look single story, ranch profile but not as wide as a 60's ranch, with a low sloped roof. These were really common where I grew up. They all had to be arranged in the same basic setup because they needed enough internal walls to keep them from collapsing while being driven to the foundation.

Prefabs never died out, you can still buy them today. But 90's developments started to move into McMansion territory.