My local guy is kind of retired but still says he works on starters and alternators.If there is one.
My closest local rebuilder was 30 minutes away. A decent guy (for the most part), and was open on Saturday. He closed and moved to Florida. My next nearest "local" guy is an hour away. And closed on Saturday. So that means taking off work, driving two hours just to give him some work and he's got the grumpiest attitude that I've ever seen for a guy who makes his living off of walk-in work. He also gave me a wrong voltage regulator and I had to make another trip back to him to get the proper one. While I normally don't use much starter and generator/alternator rebuilt parts, I have several tractors that were made decades ago and you just can't buy new or rebuilt electrical parts for them. (Ever try getting starter and generator parts for a 1939 Graham Bradley tractor?)
You advice is good, just not always feasible.
While there might not be much $$ in rebuilding car starters and alternators I think there is for heavy equipment like bulldozers.
However I am a computer guy (soon to be retired) so I may not have the latest info. And not looking to become a starter or alternator rebuilder in my retirement years
Maybe bow thrusters.