You have about 24,000,000 citizens of Texas, so maybe 12,000,000 are voters, maybe a bit more or a bit less. People didn’t turn out period. If one wants to call getting 10% of eligible voters a victory, good.
for a primary it is very good.
Registered Voters. ....... 15,099,137
Voting Age Population.. 19,502,633
Percentage Registered.. 77.42%
November 2017
https://www.sos.state.tx.us/elections/historical/70-92.shtml