Building and deploying that automation requires capital. As a result, it's largely the people who control that capital who benefit from it, not the individual workers whose productivity is increased by it.
There were people who added value to a manufacturing process by being highly skilled welders (earning $30/hr) who can push MIG wire at 30 inches per minute. On a good day, they actually average 20 inches per minute OEE because they also need to load and unload the fixture, take lunch breaks, and so on. Those welders become (or are replaced by) weld-jig-operators, who can load a buffer of incoming parts, unload a buffer of completed parts, and replace emptied spools of wire, clean up the work area, and so on, while the $400k weld cell with a trio of ArcMate robots pushes 80 inches of wire per minute.
Yes, that's a 4x productivity gain, but does the welder now earn $120 hour? No, the new operator now gets a pay cut back to $20/hr because you can train a replacement in a week (unlike a welder, who needs years of practice to manipulate a torch that skillfully). Meanwhile, the owner of the company profits at ~$100/hr, recoups their big capital investment after a year, and rakes in the profits after that to buy another yacht, or maybe a newspaper.