Earlier quoted context omitted.
>Your local water monopoly has perfected price discrimination. Since water is a necessity, the water monopoly sets the price of water to "everything you own". This says more about monopoly power abuse than problems with "price discrimination". Food is also essential, yet prices don't rise to "everything you own" (even for the poorest) because of competition.
That's called "the consumer price surplus". It's one of the major reasons that market economies are better for everyone than command economies. And it's the antithesis of price discrimination. You're right about monopolies -- price discrimination is a symptom of monopolistic pricing powers. It's not that price discrimination should be illegal, it's that successful price discrimination is a strong symbol of monopoly,…
I'm not denying this exists, just pointing out your Reductio ad absurdum is absurd and fails rhetorically. If your point is that without surveillance pricing legislation, people selling us essentials will milk us for the last dime we have, that simply isn't happening today.
> It's not that price discrimination should be illegal, it's that successful price discrimination is a strong symbol of monopoly
This isn't obviously true. For instance, airlines engages in intense price discrimination, with different fare classes, discounts, and changing princes per day, yet the industry has famously poor margins - the exact opposite of a monopoly. Same for games and movies (they get heavily discounted after release), and while you can argue the copyright system gives them a monopoly, it's only on that particular work. There are plenty of other games or movies to choose from.