Well, they were providing it “to the best of their abilities”. With those maxed out prices, they were sure as hell trying to squeez out every kilowatt. Their abilities just sucked due to underinvsetment in reserve capacity. But you can hardly blame them for that. Unlike in most states, they don’t get paid for reserve capacity in Texas (and are not required to have any either). Therefore, whichever power company invests in it will have to raise prices, become uncompetitive and go bankrupt. Its not the companies to be blamed, its the politicians/officials who set up Texas electricity market like that. Capitalism can’t work if you don’t set up and regulate markets to align consumer and public incentives with company incentives.
I recommend practical engineerings video for technical details.