If selling the odd number of spokes totally goofs up the inventory so that building a wheel won't happen for lack of the last few needed and uncertain replenishment of stock, kinda , sorta understand. Kinda.
On really more modern straight pull or weird materials, configurations ... not worth the effort. In the short run.
Shops I have noticed are closing up, selling off to the brands in a very noticeable way this year.
Next year will really be different.
The shop I used to work at from 1974-1979 sold off in the 80's and my guess the long term lease ran out.
Renewal may not have been available or viable..
A few others sold off to the Big Boys.
I am not sure the big brands can really make it work profitably.
exchange a tube? $20-25 labor won't fly well. if desperate, they can catch a few customers.