Ok, my definition of "elites" is they are the people who wrest control of the systems that sustain us all and bend them towards extracting value for themselves. They're the people who live up on the hill and extract grain from the peasants at the point of a sword. It's generational.

Peasants are not very productive and you need a lot of them, and you're continually running the risk that they're going to revolt or want a better deal.

Under conditions of wider stability I absolutely agree with you that in general "elites" want to slow or block change. The system is rigged to support them already and change is risky. When there is significant external competition (threat of war or impending social change that would overturn their control), I believe it turns out to be surprising what can be done...

If automation can replace labour as the main productive input, the "masses" and welfare seem largely redundant and significant degrowth might be seen as preferable.

I am not claiming this is pre-ordained or a definite outcome, I am saying that this line of reasoning seems plausible to me.

The tipping point would seem to be where the marginal return on investment in capital (automation, AI, machines) exceeds the marginal return on investment in humans (labor, welfare, training, etc.).

Automation replaced labor decades ago.

A 32 hour work week was suggested by USA politicians almost a century ago. Read that again - a century ago.

You're trying to reduce complex human issues to a single metric of input vs output. I struggle to convey why this is um, not smart without being insulting.