Easily avoidable sounds like something someone who has no idea how a power plant works would say.
The way the electricity system works here in TX is that the consumer purchases their energy from a broker. The broker purchases the electricity through a supplier - of which there are many - from the wholesale market. There is also the grid or transmission system, which is also maintained by another party based on where you live. ERCOT looks over all of this to balance demand and the reliability of the system.
The brokers (who the consumer purchases from) can decide how they structure their contracts with any given suppliers, and they then roll that all together for a price for a customer, including the local transmission charges, which generally wouldn't fluctuate. For the vast majority of brokers, they likely hedge their costs, so that sometimes they pay a much lower price than the consumer pays, and they make money, and sometimes they lose money (such as last week).
Since any given power generation company can charge whatever they want on the wholesale market, as generation failed last week, the wholesale price of electricity increased dramatically. This is how the de-regulated market works and whether or not it is right or wrong is going to be the discussion for another day. Perhaps everyone will be up in arms and will want to go back to a regulated market, but they should also expect the possibility for their rates to increase to hedge for things like this. Voters can stand behind whatever candidates they feel like to try to change this, or get in touch with their state reps to force the issue.