I found this article from The Federalist a good explanation of what happened.
“It appears that ERCOT, TexasâÂÂs grid operator, was caught off guard by how soon demand began to exceed supply. Failure to institute a managed rolling blackout before the grid frequency fell to dangerously low levels meant some plants had to shut off to protect their equipment. This is likely why so many power plants went offline, not because they had failed to maintain operations in the cold weather.”
https://thefederalist.com/2021/02/18/texass-blackouts-are-the-result-of-unreliable-green-energy/
There’s no excuse for being caught off guard. This happened during the polar vortex of 2019, and doesn’t surprise any rational thinker employed in the baseload generation industry. We expected it. Read post 19.