In the US, labor protections have been continuously eroded since at least the 80s, as the US Republican party has worked tirelessly (and overtly) to promote corporate interests at the expense of workers, and the Democratic party has often joined them without advertising it (for both parties, that’s where the money is).
On an international scale, international agreements, including both bilateral agreements & large multilateral treaties and various trade deals, erode state sovereignty replacing local worker protections with unaccountable judicial and quasi-judicial arbitrators who tend to side with corporations against consumers or workers, and sparking a race to the bottom when it comes to all sorts of national regulations.
For individual companies, there’s no downside in ignoring any unregulated external harms to workers, consumers, the environment, etc., right up to the point where a scandal gets so big that it sparks mass boycotts. The “free market” is utterly incapable of self policing, and as citizens we should continue to fight in our separate republics for systems which clamp down on corruption and abuse.
In Mexico in particular, the government is weak and corrupt, relies excessively on oil money for revenue, and has been fighting a war against drug cartels across half the country; enforcing better wages and working conditions is far from their top priority.