My personal experience, at least in Virginia, is not that JAWS is pushed due to anything contractual, but because it's the only thing that most know about or want to know about on the tech support side in the agencies. That also bleeds over into the field offices that are direct client service, too.
The head of our tutor network knows this, and acknowledges it, but has pretty much "given in" to the situation as well. She says that there have been previous efforts to try to get NVDA into the mix (which, to be frank, I feel pretty certain were half-hearted) but none of them were able to gain traction.
I dislike the anticompetitive nature of Vispero (and all its predecessors) as well as the insane price gouging (my opinion, even though I know screen readers are a niche market) that they have done. A lot of my clients through the Virginia Department for the Blind and Visually Impaired have very limited funds, and although the department funds the initial purchase and service maintenance agreement, that's generally where it ends. So, up until the subscription option appeared, this left a lot of folks with completely outmoded versions of JAWS very quickly if they couldn't afford follow-on service maintenance agreements.
I truly hope that NVDA keeps gaining traction and that Narrator does, too.
Brian - Windows 10 Pro, 64-Bit, Version 1903, Build 18362
The color of truth is grey.
~ André Gide