Some of this is a bit soft. Like, the 50% / 0% employment split says something about business's ability to command labor. If we had an amazing economy with 50% unemployment, this would imply a large population that businesses either didn't want or couldn't access. And the former says something very different than the latter.
The worry for me is the "didn't want" part. Automation is increasing throughput. The ultra wealthy are netting most of the value instead of humanity as a whole. Workers are getting laid off to keep profits increasing. Greed blocks mass access to surplus while the available job pool shrinks. Culture warfare is used as a distraction to vilify those who aren't staying afloat as immoral leaches.
I doubt we could get to 50% without something like UBI. The unemployed would either die off due to lack of resources or a revolution happens to extract the horded wealth by force for another cycle of history. Doesn't mean employers won't try to min/max how much they can take.