The U.S for instance which you are a fan of is wealthy and diversified because the frontiermen never left where they settled!
If they landed in the harsh Arizona or California deserts they figured out a way to survive there without leaving. And it was very tough turning some of those places into farms and vineyards.
If young Luhyas or Luos stuck it out without abandoning their villages and farmlands you would surpass every community within a few decades because you are seating on GOLD.
A village will have 10 houses (unoccupied because of insecurity) worth 50 million, the same amount is enough to put up a small factory to create employment for the villagers and build wealth for the owners.
Western Kenya and Nyanza are no different from Rift Valley, Central and Eastern. If you understand the geography, Nyanza is just an extension of RV.
A mans home is where he resides. That’s where he builds. Just like those people you mentioned up there, if I land in Machakos, I build in Machakos.
If u are rarely there nyumba ni ya nini? Have a couple of structures like this with an outdoor toilet/shower na uko poa. When u are spending more time there angusha hiyo monstrosity yako.