Ok. Youll.have to forgive this response for being limited because a) I'm on my phone at the moment and b) unlike someone like say kleinbl00 or mk, I'm not always good at coming up with super concrete stuff. So my response will be a bit more in abstract comparisons.
So about the FDA and all, no system is immune from problems and that's why concepts such as transparency and effective checks and balances are important. You can't just pick one or two examples of an organization not meeting our expectations and say "they're not working right now in this particular instance, so that must mean no regulatory body is worthwhile." That's just not really fair.
I can think of two really good, concrete examples where a lack of regulation or ignoring regulations have caused public harm. The housing/financial crisis from the last decade, to the best of my understanding, is due in part to deregulating some of the ways banks could make loans and transfer money. The result was disastrous and I think people can argue that we are still trying to recover. In more recent events, the Flint Michigan water crisis shows what happens when people decide to ignore safety regulations. Many people have been harmed when it could have been avoided.
In more abstract concepts though, we can compare regulation heavy countries like America, France, etc. with countries that are less inclined, such as India, Haiti, etc. Just looking at the them on a surface level from their roads to buildings to public safety you can see how regulations can have a big impact. For a good example, if you were to compare The Mississippi River and The Ganges River, you'd see the effect environmental regulations have. These things do male a difference. Laws that are meant to protect tenants such as rental laws and building codes give us healthy and safe places to live and ensure they stay that way. Workplace regulations really do ensure that our places of employment are safer and that we're at least somewhat protected when it comes to being treated fairly.