Commercial customers like factories and empty offices cutting usage can still make a serious impact.

I expect they would have mostly been shut down at $1200.

Really it looks like retail electric providers in Texas are structurally disadvantaged vs generators, carrying an unlimited obligation of service vs getting the spot price set to the regulatory maximum.

25000 people.

I recall hearing that it was 29K on Griddy (myself included) before the storm. I've also heard a little over 10K were left to be transferred when it was shut down. I'm not sure exactly how many were exposed to the 4-days of artificially pegged prices.

I've also discovered over the past week that there's at least one more wholesale-rate provider, https://www.octopusenergy.com (specifically, it's OctoFlex plan).

Yeah, that's why I added the qualifier. It seems likely that most of the spot load was going to home heating (with less flexible large loads having contracts).

Ah, I misunderstood your comment. You meant "those retail customers who have fixed rates", but I read it as "retail customers, who have fixed rates".