That’s not laughable in the slightest to anyone who knows history of machining. There are fewer and fewer machine shops, and at the same time the machining centers are becoming more and more sophisticated. Sure, operating CNC mills requires significant expertise, but so did manual machining. We used to have hundreds of thousands of machinists in this country, making various parts for cars, household appliances etc. Now it’s all factory made. Just because some existing process requires expertise, doesn’t mean that we cannot come up with a new process that will not need that skilled operator as a step.
However, completely wiping out a process (replacing sheet metal fabrication with plastics) is not particularly "automation" of said process. You've just changed where the expertise is rather than automated it away.
Replacing injection molding machine operators with 3D printing machine operators is automation because it makes some people go away/requires less expertise.
However, even before Covid, McDonald's was rolling out touchscreen kiosk and app ordering. So, there has definitely been automation in that sector.
The paper is ... kinda odd ... because its methodology considers machine operators (injection molding machine operators, lathe and machining center operators, etc.) to be some of the most automatable. That's a pretty laughable idea to anyone who has tried to run one of those machines.
Yeah, 20 hours of training got me to the point I can run a CNC mill. However, I wouldn't say I'm good at it. I touch off incorrectly probably 1 in 20 times--which likely blows a part and breaks an end mill. I sometimes don't leave enough clearance to the vice jaws--which certainly breaks a mill and possible damages the machine itself.
I think it was NYC CNC on YouTube that had a whole video of the various fails he's had with CNC milling machines over time. Anyone who has used a CNC cringes at that video because we have all done exactly the same things.