Sooner or later he will need to take on an apprentice - it would be nice if he can start a school like that.
You mentioned electronics, and the Japanese tradition of craftsmen making the whole thing brought to mind the slightly eccentric electronics of Susumu Sakuma. He (was?) making retro audio amplifiers on his kitchen table at one point.
Every independent watchmaker has to deal with repairs, but once you pass six figures or so for a single timepiece you don't see them outright returned much anymore (statistically speaking).
Even at high five figures you don't see them returned very often, but you do see a valley of returns at the low five figure mark ($10-$30k), or at least a lot of reselling. This is the ceiling at which a watch is "affordable" for people who aren't wealthy if they are well-paid, have few to no obligations and are fiscally irresponsible, which often results in buyer's remorse. This is one of the reasons why it's comparatively easy to find a mint or near-mint preowned watch at a significant discount less than two years out from original production year for a lot of "entry level" timepieces from the most high end brands (Lange, Vacheron, Patek, etc). You won't find similar discounts at the mid, high or ultra-high tiers within these brands, because they circulate less.
Moreover, buyers who are more likely to regret their purchase typically buy more recognizable brands. Buying from an independent takes a higher commitment to the art of haute horlogerie because virtually no one is going to recognize, even among people who recognize more than just Rolex. The market for reselling an independent-made timepiece is also lower (though in the case of someone like Smith or Dufour, this is probably not a concern).
Source: Watch hobbyist, I own an A. Lange & Söhne and Nomos Glashütte, frequent watch forums and read watch blogs.
Another example is that I build 1:10 scale truck bodies for radio control cars. One takes anything from 2 to 12 months, depending on the amount of detail I'm willing to put into engines, opening doors/hood/trunk, backlit dashboard, and so on. I'm often asked to sell them, or to take commissions. I always refuse, as one (basic) body, counting time and materials, should go for at least $10k to be even marginally profitable.
I've given some away, which is a lot more rewarding than selling one for $500.
I'd imagine a 'return' would be a trip to the chap's house and personal attention until the watch was working properly. My old hand-assembled clockwork camera (a mass produced item compared to the mechanisms in the OA) has worked faultlessly for around 15 years. And I bought it second hand then.
Also, I believe that even amongst the highest echelons of independent watchmakers, few are able to survive on their brand alone and rely heavily on either restoration work, work for larger more established brands, or a combination of the two. Even guys like Dufour and Voutilainen, two of the most respected independents in the watch world, partake in outside work for the big brands like Patek, VC, and AP.
If anyone is interested this is a post on a fairly recent visit to Beat Haldimann's workshop[1]. One of my favorite articles on these kinds of visits is from 2006 and involves a visit to the home/atelier of a former French kickboxing champion turned watchmaker[2].
[1]http://www.watchprosite.com/independents/a-true-discovery-my...
[2]http://www.watchprosite.com/richard-mille/alone-with-the-rm0...
I wonder if those huge street 'watches' are actually apprentice pieces? The large scale of the movement making them easier to make and, I presume, less susceptible to small errors in the making of the parts?
There is only one independent watchmaker ever who has become a multimillionaire (approximately CHF125m net worth) and that is Franck Muller. But his business (which he no longer owns) is a vast, mass production enterprise.
It is, though, a kind of double edged sword. On the one hand they continue centuries-long traditions, on the other hand they get coöpted by hipsterish connoisseurs who work for companies feverishly contributing to the demise of traditional craft in the name of efficiency and doing things better.
In addition, many of these products are not unnecessarily anachronistic (like say making an electronic device with discrete components and hand made pcbs).
Bravo to these people.
[1] By precision I mean they must follow a meticulous process to achieve near-perfection of result.