As someone in love with fountain pens and ink, I can tell you that there are absolutely wealthy pen turners, private designers, and the same with watches.
I don't have the socials, so I don't see things like what you mentioned.
probably would make more $ from it if you were a YouTuber or TikTok creator and did "watchmaking" content.
Watchmaking can take a heavy toll on eyesight, due to working with magnifying glasses on tiny parts during decades. Also each brand has unique processes and machinery, for which they have expensive learning courses.
Thus they would rarely consider applicants past their forties even if they have experience and favorable relations.
It’s not likely to employ millions of people, but there will be demand from people with serious money. For instrument making, research labs will need specialized glass parts, for example; for painting maintenance, museums have a need to keep their centuries-old pieces in the best condition. For watches, if you pay a few million for a watch, paying 10k a year for maintenance should not be a problem. For that money, you can make a decent living of 20 customers a year in many countries.
[1] This model! https://www.fratellowatches.com/citizen-homer-second-setting...
He was a true master of his craft and built a successful business based on his exceptional skill. He Was well known for his craftsmanship and his remarkable ability to repair virtually any watch or clock, no matter how complex.
Jewelers from across the city would bring him pieces that no one else could repair. For antique and vintage timepieces, he would often fabricate tiny replacement parts by hand when originals were no longer available. When he retired, very large companies would still come to his home to repair incredibly expensive pieces. He liked to tinker and would quietly work in his little home shop, pipe burning, radio playing, and visitors coming throughout the day to have him fix things.
When he passed, he had 10's of 1000's of watch parts in all these little bags that were all tagged and in boxes. We ended up giving them away to one of his customers who own several Jewelry stores. Had I known I would have offered them to this school along with 100's of watches he kept for parts.