Why do some businesses fail?

Beyond the philosophical question, I see some of my corporations where the lag for their products is in the billions not doing well. Why is that. I have turned their target salaries to 100, checked contracts to avoid higher end goods above their current rate, and even purchased down some high stockpiles of surplus, but they can't seem to break a profit. What else can be done to trim fat?

Some corp types just will never make it. A limited number though.

It's important to upgrade your corps to the max if you are trying to sell on the world market. Are you doing that? Often you wont see much, if any, profit until they are mostly upgraded.

Corp hiring needs to be at 100%, thats a must.

Although it seems minimising wages is cost cutting, that is not necessarily true. The welfare of your corps is very important, higher welfare = higher production. Less than 100 welfare wont let many corps make a profit. So dropping your wages to 100 REDUCES welfare, and if your country welfare is below 100 too then you have a recipe for no good. At least double your salaries.

Quality of supply goods for your corps? The default beginners advice is to buy at 170 ish so producing a product of about 250Q (this is state corps, upgraded). Using cheap stockpiled goods is good, but keeping the output quality is pa