> They’ll buy your entire life from a data broker and charge you more because yesterday you accidentally viewed some Lamborghini seat covers.

You're describing incompetence. You're not actually rich just because you viewed something by accident which means you're not actually price-insensitive and they just lost the sale to someone else. That has nothing to do with algorithms, incompetent companies put themselves at a disadvantage and make fewer sales than other companies all else equal, and the ones that are sufficiently bad at it go bust.

> They’ll calculate that you have less willpower on Thursday nights and change their advertised price from $10 to ON SALE $2 off $12.

They do that regardless of whether it's Thursday.

> They’ll just do coincidentally use the same algorithm to determine their price as all the other stores do so they don’t have to worry about competing on price.

This again has nothing to do with algorithms. They can do the same thing by just looking at the prices other merchants are charging and setting the same ones, and if you really want to prevent this then the law you want is the one that prohibits manufacturers from enforcing "no sales below MSRP" against retailers.

Because in a market with a large number of retailers, the individual retailers all have the incentive to defect from a price fixing scheme, because increasing your market share from 0.5% to 20% by having the lowest price when those other idiots are refusing to compete on price is worth way more than having slightly better margins. This is why it's important that the number of competitors be large instead of small. Laws should be directed to ensuring that rather than trying to micromanage a consolidated market full of incumbents so large they can buy the government anyway.