Companies do not fuck around when an AG comes around. Enough complaints, or complaints that are ignored, is a quick way to get sued by the AG. The AG's office has extensive resources to easily win in court, even getting your entire company's - including parent and children companies - banned across the entire state.
It's also pretty easy to get the AG involved. You have to provide a decent amount of supporting documentation, but most states have an online form you can file.
As an example, 20 years ago, a company tried to deny me a mail-in rebate. This was while my state AG was actively suing them for not paying rebates. I spent 30 minutes filling out the form with the required evidence. Receipts, etc. A month later I had my $15 rebate check, no additional questions asked.
Shrinkflation is smaller quantities and/or higher prices. This is actually tracked in a variety of places.
Changing to a cheaper recipe/supplier is very hard to put metrics on, and isn't tracked anywhere that I know of