I imagine as businesses move away from NY and SF, they want their stock exchange to move with them, and for similar reasons.
The main reason to move away from the NYSE or NASDAQ is if you don't like the rules those stock exchanges have.
“Well, we IPOed!”
“Congratulations!”
“…in Texas.”
“Do you need to use me as a reference?”
1. Texas is a corrupt state and you can bribe your way in to power
2. No income tax