Ah sorry, I just assumed you were a dev trying to get into contracting given the context.
To answer your question a bit better, I don't see much career growth per se, there's certainly no ladder I am climbing, it just becomes easier and easier to find work over time thanks to prior experience compounding. You get to choose nicer contracts and work with people you like.
There's a lot of potential for personal development though, and you can choose to spend more time on developing recurring revenue and "productifying" your expertise instead of just selling your time hourly.
Focusing on an industry domain (rather than toolset) seems smart. It’s difficult to be productive in new/unfamiliar knowledge domains and I’m sure buyers understand that.