Arizona has fairly consistent and predictable weather, decently reliable power grids (with access to cleaner energy sources like solar, hydro, and nuclear), and is pretty seismically stable. Plus Phoenix has been trying to set itself up as a bit of a tech hub for a while now so you have access to an existing market of skilled labor plus a supply to fresh talent from ASU (and the other universities).
I’m not sure if it counts as underground (it’s been around for ages), but if you’ve never thought about how your shoelaces contribute to the overall fit and comfort of your shoe, I’d recommend giving Ian’s shoelace site a visit.