Sure, robots cannot eliminate all jobs, but they can significantly decrease the number of them. In McDonalds example, cashiers disappeared, but new servers did

Sure, robots cannot eliminate all jobs, but they can significantly decrease the number of them. In McDonalds example, cashiers disappeared, but new servers did not magically appear, so the total number of jobs has decreased. The same way, in "online order" example, author has not realized that while the human still helped with the order, the electronic system likely allowed them to fire one of the cashiers. I am not sure how elastic the labor supply is -- but if it is not very flexible, then even relatively small changes can affect wages a lot.