We're heading this direction. There's a number of industries which technology has enabled them to move closer (or completely into) a manufacture-on-demand mode

We're heading this direction. There's a number of industries which technology has enabled them to move closer (or completely into) a manufacture-on-demand model where it's economically feasible to have small production runs (sometimes of even a single unit). T-Shirts are probably the first one I am aware of which got there. But strangely enough, Guitars are moving that way. It used to be to get a signature series you had to be a pretty big artist. These days, there's players from cover bands getting signature series! You look through all the lists of signature series guitars, and quite a lot of them have been released in just the last ~12 years. PCB's are going there now too - I've read on HN itself hobbyists talking about how cheap it is to get individual custom boards printed for them for projects shipped from China. Manufacturers taking production runs of less than 100, and happy to do it. It's worth noting - production on demand doesn't provide any guarantee that the products will have good longevity. In fact, many printed-on-demand T-Shirts are pretty crap and you end up tossing them after a couple years.