Your experience is not surprising. In the last decade the old guard of knowledge has retired and been replaced by folks that charge the same rate but don’t have the level of hands on experience too back it up. Where in the past you might have called up the old dude at the factory and might have mixed up a batch and saw the same thing, the new guy isn’t going to even have access to the stuff without a mountain of paper and an authorized test plan. Even if he did see the same issues corporate processes would prevent him from disclosing and sometimes even addressing the problem.

This sort of stuff is happening everywhere in the us manufacturing economy and why China is absolutely kicking our ass in production.

The Chinese Built up an army of experts doing things just like you do in their garage and small factories. All folks with hands on real experience with materials and processes and they are kicking our ass at absolutely everything manufacturering wise expect super complex high capital and even in those areas they will be on par within a decade or 2.