Now you know why my forecast was as stated for Don.
I had never seen a tropical storm develop so poorly to where the convection wanted to fire over the Yucatan Peninsula more than than the center of the circulation. Furthermore, the circulation was tilted with height most of the time and not upright. You don't get good updrafts when it's sloped!
I seriously think the ongoing drought played a major role here. With virtually no soil moisture in the TX region, a huge hot and dry air mass has been sitting there. All of the moisture literally evaporated out of Don in that air mass. If TX had not been in a drought, there would be far more moisture in the air to allow further penetration inland. See, even little things like the amount of soil moisture can mean a lot with large systems.