yes, I have done that quite often. I do look for a machine that isn't really worth restoring.
The big problem here is that often it's the same part that keeps getting broken/lost, so if you find a machine that only needs that part, often you'll find more machines without it than with it. So you have to decide if the first machine is really worth getting up and running, or if you are better off finding a nicer condition machine to restore.
I have a lot of machines that are only for parts. Sure, every single one of they could be made to run again, but then you have to find another donor machine for the one or two parts I needed that I took off.
I told my husband that I'd take this summer to try to rehome my unwanted machines, and what I still had come fall would be stripped of the easily removed parts and the carcass sent to the dump. Fall begins on Sunday, and I have not rehomed a single machine.
I have plenty of machines I'm keeping that are worth restoring and they all have all their parts. I don't feel bad about this, even if there are getting less each year, there are still way more vintage machines than there is interest. I will stress that I'm talking high arm style machines, mostly made after 1900. When you talk older machines, it's a different story.