Add this to the list of industrial sectors that are profitable but for the resources payment. Raising the default profit tax rate for C3s would be sufficient to achieve the same objective.
The industry is extremely profitable. countries are making profits and prosper. the money comes from corporations.
The setup of all corporations is such that they are profitable, either in a country or an enterprise.
There are conditions that can change that, like some materials that are not available, or they are not upgraded, or the there is a surplus on the market. There are also conditions that can make them extremely profitable.
The economic game is very profitable but not trivial.