In other words, regulatory capture at its finest, over the backs of the poorest in the country.
To attain change, enough people have to:
1. Correctly identify the source of their misery, because it ain't [insert scapegoats].
2. Find others who agree with them.
3. Make a plan for effective countering of 1.
4. Use intestinal fortitude and endure temporary setbacks to achieve 3. to overcome 1.
5. Prevent 1. from ever happening again structurally, culturally, and through vigilant participation.
The 0th problem is the political operating system is captured by criminals and power has centralized grotesquely in ways that defeat the fundamental function of separation of powers. All elected officials corrupted by lobbyist bribes need to face accountability and have a code of ethics and integrity, because continuing down this path is the road to ruin.
Are there any common-law jurisdictions in the world where having products on sale in a supermarket is not generally considered invitation to treat but as an offer to sell?
One reason it works this way is that treating displayed items as an offer to sell would leave it unclear to whom the offer to sell would be made. Clearly each item on display can only be sold to one of the many shoppers who sees it, so they can't all be offered the sale. There are several other reasons too, like different customers being offered different terms of sale based on loyalty program membership, promotions, student or senior discounts, etc.
Here is the Wikipedia summary: https://en.wikipedia.org/wiki/Invitation_to_treat
As the article says, the term in various US jurisdictions may be slightly different, like invitation to bargain, but the basic concept is the same. (I'm ignoring Louisiana entirely, which has a completely different legal tradition not derived from English common law.)
If the price on the shelf were an offer to sell, then you would be contractually obliged to buy everything you picked up. The offer comes instead from when you pass it to the cashier, which is why I'm saying for the third time on this thread, if you don't like that price walk out and leave the goods at the checkout...see if they find it more fun to put all your goods back, or put the correct prices on the shelf! If a group of people did this at every till the store would be effectively closed.