> Not quite, prices capped first. Then when that was not enough rolling blackouts where implemented

Again, no. The cap was in place before the floor, but was never binding: they did blackouts before the price hit the maximum, not after.

> As rolling blackouts where implemented by people paying wholesale rates they obviously have an incentive for excessive blackouts

The decision to do blackouts was made by ERCOT, not by transmission operators or power retailers. (Retailers are the only ones who have an incentive to do blackouts, though transmitters generally also have a retail operation.)