I have no idea how tall Dewhurst is. I’ve never met him. Perhaps that’s why he’s lost runoffs in 2 consecutive election cycles for 2 different statewide offices.
Ted Cruz was very energetic and very well organized in running for 2 as statewide offices in a very populous geographically large state. He talked to lots of groups and talked with thousands of people throughout Texas, while Dewhurst stayed in Austin and talked to insiders and lobbyists.
A recipe for losing against an active campaign.