One would hope that the Sanborn engineer calculated or tested what happens if the capacitors are both at the high end of their specified tolerance while the thermal cutout is on the sensitive side of its tolerance and the ambient temperature is at the maximum specified?
Don't be so sure. Or if that engineer did, that a bean counter later decided that this new (untested) capacitor or thermal cutout has roughly the same specifications but costs 10c less can save us x $ a year.
Normally, I like everything you write. But those two paragraphs suggest that you are CRAZY.
There is no qualified engineer or bean counter at that outfit. Just a handy entrepreneur who cobbled together an air compressor that worked and then decided to go into business making and selling them. Or some other such equally cobbled together operation.
To be clear, I'm not knocking that business model. LOTS of companies start that way. Some stay that way and some get serious and hire the required talent as they grow. The latter group usually live or die based on how well the boss accepts the advice of the talent he hired. I can hear it now..... "What do you mean this motor isn't good enough? It worked when I installed it! We are not buying that motor you recommend! It will devour all my profits and I won't be able to make the mortgage payments on my yacht."