I'd guess all that crud that got inside the switch had blocked the contact hard enough to break it off. I'm impressed that the replacement switch was still available.
It’s always fun working on CNC machine boards for companies they always pay pretty good I usually have flat rate with them companies specially fun, tracking down all the different switches they have and tactile buttons
16:55 I would have still tried to repair that contact on the original switch by soldering a short piece of copper wire to it or even making a new contact from 0.5mm brass plate.
Yeah it needed to be 100% reliable though, if I could not get another switch I absolutely would have tried to repair the contacts, I do have a spot welder to attach bits on to the remaining contact.
