I think the thing is when people talk about prefabs (in the UK) they’ve probably got more of a ‘Grand designs’ inspired, Huf Haus, on a nice secluded rural plot sort of image in their head, the reality is most people can’t actually afford the price tag for a well made, off-site manufactured timber frame structure, plus the site, services, planning permission and labour to “just chuck it up”…
The interest in ISO based tiny homes is all about affordability, the main thing that is missing from most housing options today.