I wouldn't go so far as "most of us". Having a home is a necessity; having a home with "character" is a luxury. Inexpensive housing needs to exist too.

A home with no character is called a prison cell.

No, it's called suburbia.

That escalated quickly

Actually prefab houses can have as much character as any other suburban house (many will argue this is zero, but even those people will get an idea of what they can look like). Several of my neighbors live in one, and I didn't even know if for years: they look like a normal house. The need to bring it to the lot on a truck places some limits on the size of rooms and where walls much be to resist shipping issues. However a quality mass produced house is cheaper than regular construction.

Manufactured houses earned their bad reputation though. Many of them are/were junk. A lot of them are made by the same guys (and quality) who make trailer houses. Many city (suburban) codes, or HOAs will not let you put one up at all. This means that you don't see many of the quality ones. Most people are not actually qualified to judge quality of construction, some of them even today look nice for 10 years and then the maintenance nightmare begins: the parts are not standard home center sizes so it is a lot of labor to fix anything.

For most suburban houses you can take tens of thousands $$$ off the cost of new construction, get a good floor plan, and have your house built in 1/4th the time as regular construction. Anyone who is thinking about building their own house should look into this option (remember what I said about quality above though), but there are more energy efficient options that I think you should pay extra for even though it drives you back to site built.

I was frankly shocked the first time I saw Blu Homes. They look a helluva lot nicer than just typical 50 yr old wood frame ranches I see in the Peninsula. Including the one I live in.

If we're talking about cost here, "character" is a luxury. I personally would welcome lower rent (or lower building costs) in exchange for something generic.

A while ago, I read about a company in Germany that manufactured homes that were delivered flat on trucks for assembly onsite.

Maybe it was this place: https://www.huf-haus.com/en.html

So, these homes lack character?

In the US, Sears used to sell homes in a similar fashion.

The problem with trying to do this in the US is the diversity of building codes across the country which limits the economy of scale significantly.

Mass producing homes would likely mean more density/taller apartment complexes, not prefab mobile homes. And the necessity part of housing is having a decent home you can afford, having one with outward 'character' is a nice-to-have.

Then we can mass produce parts of housing and add on additional "character" to those prefab, modular parts.