Why would the politicians allow this, surely this backfires hard on them
My 10% cut-off is probably wrong. It's unlikely to have a noticeable effect on the top 5%. (Zuckerberg wouldn't notice if his home electric bill went up by 200-500x.) The interesting effects will be at a lower premium over median income.
TIL that the Robertson-Patman price discrimination ban (15 USC 13) doesn't work the way that I thought that it did.