That's a pretty useless comparison between sectors, as you're excluding the manufacturing workforce for Apple, but only partially excluding McDonalds (most workers are franchisee employees).
Or look at a waitress in a restaurant. The math will be similar. A service job can't pay you a 6 fig salary outside of a few niche roles. That is why the "it's ok, we can all get service jobs" is a lie. That's a pretty crappy life.
Way off topic from the original article but "we can all get service jobs" implies a reality where the cost of any manufactured good and food is approaching 0. In that reality, you would only ever need to spend the money from your service job in other services.