They still require more energy than the end product produces.
That obversation is moot. They transform the coal gas into a myraid of products on which modern life is pretty much dependant.
In most cases they are the low cost producer
Welcome to entropy.
It takes more coal energy to make electrical energy.
It takes more electrical energy that you get light from the light bulb.
The goal is to take low order energy that is not useful and create a higher order energy that is useful.
You have no use for coal dust but have a great need for electricity. You have no need for corn stubble but have a great need for liquid fuel.
There is a company using plasma arc to gasify garbage. They are not using governement money and they are making a profit selling their product. Their buyers are making a profit in reduced landfill cost and using the syngas to generate electricity. Right now the most feasible place in America for their technology is NYC but are having problems with corupt politicians. The mob makes alot of money in the garbage business. I personally think it would make more sense making liquid fuel instead of burning the syngas because coal is cheap and liquid fuel is expensive.