Machine learning is an interesting case, in that the gap between theory and praxis is quite wide.

You can basically create, run and evaluate a model within 10 minutes (e.g. with scikit-learn or Tensorflow). It would even be an acceptable model that might solve your company's problem.

But you have to plan in a few years of deliberate practice to work through statistical learning theory and its prerequisites to get an overview and to be able contribute to the scientific or open source efforts in that field.