There is a very important reason. Non-renewable natural resources are going to end some day. Basically, some years from now, there will be no more coal to be extracted from our mine. What will happen to the population when there is no mine? What are they going to do? How can they live? What kinds of jobs are they going to have?
We have to build an industrial infrastructure that will allow the population to have a high standard of living after the mine closure. We are in the business of sustainable development. The only way to achieve that is if we can build an industrial infrastructure that doesn't depend on coal.