So with mineral rights in Texas, could you just buy/lease them out from under one of your rivals/enemies and just bulldoze their buildings for the lulz? "Sorry, I just really needed that teaspoon of dirt from under your multimillion dollar factory". I guess that's the whole idea of the insurance/waivers, so do you need 50% of the owners of the rights to agree?

Also, I heard that Texas was the best place to build things (cf. Abundance by Thompson & Klein)

Well you need to find something to exercise the rights I would assume.

He couldn't get insurance without a waiver. He couldn't get a mortgage without insurance. So he didn't want to invest his own cash exclusively.

This is not only Texas. It is everywhere. It is why "real estate" is a descriptive term that exists.