This is 1000% false and misleading. My Dad was a journeyman machinist and many of his friends were highly sought after welders in the area we lived. These guys could weld anything anywhere and exceed quality criteria.

Welding is an art and at a certain required level of performance it's not something you teach, but find the folks who have the drive to be that good and want to weld for high precision requirements.

What you've linked is a run of the mill welder. My Dad machined classified parts for USG and NASA. When they'd get those jobs they would go to the guys who had a reputation to be able to produce the die to the spec required. Messing up a multi-ton die of a specific quality could cost hundreds of thousands of dollars in lost material and time. You don't make $48k on those tolerances, even back in the 80s.