Who may also have margin competed away.

And to the overall economy - more stuff with less resources is growth. But that's all going to capital, look at the s&p500 vs wages over the same time period.

OP owns a CNC shop which is almost tautologically capital

Saying a CNC shop is comparable to a an S&P500 company because they're both capital is like saying a retail clerk is comparable to an NFL player because they're both labour. While true, it's not really relevant to this discussion.

I agree the parent comment should be more specific, but his point stands: gains are going to a few companies that automate everyone else's processes or benefit from the huge economies of scale that automation provides.