> If you choose your niche well you will never need to look outside of it until you have ramped up your skills for your next specialisation.
... or until your niche dies out. This is my situation at the moment: my niche is very profitable but likely on its way out in a year or two. Related fields are either very boring or much less profitable. If I had stuck to a more generalist career, I'd have made less money for a few years, but maybe my employment would have been a bit more secure in the long run.
While I love to learn new things I do so on my own time.
My clients only ever see the expert because I only ever agree to do things that I know I can do better than almost anyone else they can hire.
This is in my opinion one of the most important things in building a successful consulting reputation.
If you choose your niche well you will never need to look outside of it until you have ramped up your skills for your next specialisation.