The FDA regulates (or fails to regulate) many different classes of products (drugs, biologics, devices, human cell and tissue products, supplements, food, tobacco and nicotine products, etc). FDA's authority and its effectiveness is extremely variable across these classes.

My sense is that the traditional drug and biologic drug parts still work reasonably well, but the biggest problems lately are coming from devices and from human cell and tissue products (and with products that are being pushed into those categories). A lot of this is due to the ways the laws have been written (due to lobbying and legislative capture), but some of it is undoubtedly a result of regulatory capture and incompetence.