For me, I'm not so sure. I am working on multiple screenplays and this is my main focus alongside my Medium platform. I'm not really interested in starting and worrying about a business since like Mark says it'll take too much time away from my own writing.
The problem with my dream is that it's extremely difficult to make money off from it consistently. So I don't really mind having a job which pays well and allows me to focus on writing my own stuff in my spare time. If that makes any sense. I've tried the freelance route and the amount of effort and time it takes ultimately drained my energy away for some reason.