Would you be as happy if your revenue wasn't increasing like it is? Imagine 10 to 15 years of stagnant growth. Would the fact that you've decided that path be enough to make you happy?
I knew this would be my full-time job eventually. My field is very research-based and very niche. It took over 10,000 hours (I guess I'm a Gladwell expert now) of unpaid research and experimentation to get to where I am at.
Was I happy doing it? Tough to say. I know that I wasn't sad when I worked on it, compared to working my "bullshit" data science job.