Long post that.
I think the first paragraph misses the point of location of wood. I imagine the trees used in the 50s and 60s were American and there was likely a large supply of old trees without protection that were not considered desirable. I would be surprised if the wood used by Fender now isn’t sourced from purpose grown forests in another continent.
Absolutely agree that instruments such as electric basses are unlikely to have improved with age. Maybe people’s recollection of how they were at the time was dictated by taste and fashion?
A labourer will never be as consistent as a machine no matter how experienced. You’ll get a few Friday afternoon or Monday morning results, whether that’s better or worse.