1. It doesn't really - it changes them. Changing from horsepower to cars eliminated the jobs of people that hauled horse manure - but created myriad of jobs for caring for, fixing, maintaining, selling and otherwise dealing with cars. The mistake here is that people see where jobs disappear, but don't see where they appear since they don't know where exactly to look.
I don't really see how car can be seen as exemplary labor saving invention. Steam engine, electric engine, radio communication, computer, internet sure, but car?
It's just a technology that allows you to build artificial horse that drinks stuff you can mine from underground and shits in the air you breathe instead of on the street you walk on. It surely saves some labor, but it turns so much on its head by increasing mobility and allowing for actions that were previously impossible that this labor saving part is pretty minor and is easily offset by paradigm change that car brought by.
