What we really need is “actual modular” houses built like LEGO blocks, with no more than 20-30 different types of “parts” that can be assembled into houses of any size/configuration.
So that if you need to add a room, it can easily be done, if you retire and need to remove a room it can be done easily too.
I came up with that idea for modular building parts in high school. Would have plumbing and wiring pre-installed with quick disconnects, so they would snap together like Legos. Structural integrity might be an issue though in earthquake and wind storm areas.
It's been done. His name was R. Buckminster "Bucky" Fuller and the modular in question is his geodesic dome home.
Geodesic dome construction could not be more simplistic, as they are made of simple triangles bolted together.
The dome is itself the structure and no internal load bearing walls are required, so the rooms can be where and how you want them to be and then are relatively easy to change, especially when compared to traditional structures.
Plus, unlike a trailer in a trailer park, a dome is a challenge for tornadoes as their shape and robust structure handle wind very well, same for snow loads.
Aesthetically, they have a love it or hate it appeal and can be an acquired taste, sometimes never acquired.
But with low material requirements and simple construction, they are fairly cheap to build and can be very energy efficient. Not a bad compromise.
If unique is what you seek, Bucky Fuller had it.