I'm not saying it has never been done successfully before, but I'm trying to think of other manufacturers who have successfully diversified in this manner. I guess Fender and Gibson make amps and strings. But I'd imagine they are significantly larger companies than Upton.
And a banjo company like Deering makes straps, strings, bridges and picks. I wonder how many such makers who diversify manufacture their goods in-house. As opposed to contracting with other makers.
And I'm not sure how much examples from other businesses - even other musical instriment makers - translates to the somewhat small world of upright basses.
I hope the folk at Upton all the success in the world. And I readily acknowledge I'm even more ignorant about business than I am about playing upright!