"labour's share of revenue has shrunk compared to the share taken by capital (and also high-level executive type employees). And this causes, or is at least related to, problems with society as a whole."
In America possibly.
But remember the missing part from this piece: globalism.
These are not 'American' companies anymore. They are global. Often with considerable ownership from overseas - and employment.
So - while the American lower-middle-class has not been doing as well - India, China, and big chunks of the developing world have been growing gangbusters.
They're all hiring in India.
For every middle-class American in stagnation, there's 2 Asians and 1 South American who are 'on the up'.
I'm not saying it's better, or needs to be this way, or making any kind of moral argument, rather just pointing out that most companies post-2000 simply can't be spoken of entirely in the American context anymore - and the story looks different when you look at it more from a globalist perspective.