The thing is it’s been like that forever. Good products made by small- to medium-sized businesses have always attracted buyouts where the new owner basically converts the good reputation of the original into money through cutting corners, laying off critical workers, and other strategies that slowly (or quickly) make the product worse. Eventually the formerly good product gets bad enough there’s space in the market for an entrepreneur to introduce a new good product, and the cycle repeats.
I think what’s different now is, since this has gone on unabated for 70+ years, economic inequality means the people with good ideas for products can’t afford to become entrepreneurs anymore. The market openings are there, but the people that made everything so bad now have all the money. So the cycle is broken not by good products staying good, but by bad products having no replacements.
I don’t follow Mexican politics closely, but this could be part of an effort to curb obesity. I’ve heard they introduced taxes on sugary drinks for this, so this might be another avenue.
If people are wanting cheap snacks, and private companies are only making unhealthy ones, you can introduce regulations to micromanage what they can produce, or you can introduce a complex taxation process to disincentivize sugar snacks. Or you can introduce your own product that meets a perceived unmet demand in an underserved market.