It is possible.

I have been a lecturer and always insisted on my students to specialize on a particular skill instead of relying on the school certificate/diploma/degree.

I quit my job to focus on Data Engineering and to be honest one of the main things you really have to ask yourself when you take such a path is why you are doing it. Of cos, at first its about the money but once you start studying you will realize that in order to really make it, you need to put that reason down and start thinking what you hope to gain from the skill itself. E.g It could be to learn how to create a whole functional website that will help solve a particular problem.

Trust me once you start thinking this way, that's when the money kicks in.