Why don't the Ulama do something to ensure proper supervision of the meat industry to eliminate doubt?

Answer

Halaal meat products cannot be acquired from non-Muslims. The only way is to abstain from buying meat and chicken products from non-Muslims. The calamity of buying meat from non-Muslims has developed only in recent years since the time the halaal certificate industry was developed. As long as Muslims purchase their meat products from non-Muslims, they will be consuming haraam regardless of any system established to ensure that only halaal is acquired from the certified business place.

It is impossible to effectively police the innumerable businesses, processing plants, shops, supermarkets, restaurants, etc. to ensure that only halaal is served. Experience has proven that even a single plant cannot be correctly supervised. Now that Muslims have become accustomed to consuming meat and chicken processed by non-Muslims, almost all inhibition which Muslims used to have for haraam meats and for purchasing from non-Muslims has been eliminated.