Main reasons are a stable geology and climate, access to reliable water via the salt river project that was designated for industrial use, and the historical semiconductor presence that is already in the area. The local universities also have a strong focus on tech.
Arizona seems a particularly bad place to choose freely.
Fabs consume enormous quantities of water and Arizona (and the sw) are already in precarious position, and not even a semi viable theoretical option like desalination possible in the future
A sweeping statement, like plastic is recycled. It is more complex than that.
It is energy intensive (and expensive) to recycle both low purity and ultra pure water (UPW) used and for some fabs it is just 40% [1] and there is no consistent globally adopted solution, most of the tech used is still evolving and not implemented everywhere.
