But at some point a human will add so little value that they're not worth the price.
But the reality will probably be that plumbers and builders become the next tech bros telling us to learn tiling. Just go with the flow I guess. If tech becomes automated, move to the next thing.
Instead of worrying about bullshit metrics from times gone by, let's ask questions like "what happens to the happiness of plumbers and electricians when they realize that they too can relax and let the machines take care of the grunt work?"
Just a guess…