It's actually pretty interesting - cobblers used to be pretty comfortable doing ONLY their job when almost everyone wore leather shoes, but when people started changing it up, they tried finding new ways to keep their jobs. They had trouble finding something that no one else were already doing better, though.
Around the same time though, the ironmongers were ALSO not able to live with the new market, and they couldn't adapt and died out. Ironmongers were who the people would go and get their keys cut, so as the ironmongers died and the cobblers refused to, they ended up doing both to make up for the loss of one!
