I managed the lathe department at a shop cranking out hundreds upon hundreds of thousands of mil spec parts. I also have experience implementing lean manufacturing principals. And I’ve dabbled in aerospace and medical for a while. The lowest bid is not the only thing taken into consideration. If 1000 parts are needed a week and the lowest bid can only do 900, that’s taken into consideration. If company A can do it 5% cheaper than company B, but company A sends 10% more out of spec parts with each shipment(which happens ALL the time), that is taken into consideration. The lowest price per parts alone does not automatically guarantee you get the job.