I've heard random uber drivers on the other side of the world talk about Dogecoin so you might want to include crypto in your list of why less people need to work now.
Those Uber drivers either have confused unrealized gains with wealth, or have realized those gains by leaving someone else holding the bag. Probably someone else just like them.
As for other examples, housing is another popular one.
Housing market is same zero sum as OP described determined by investments in real estate instead of other assets
Any other examples?
Over the long term effectively 100% of all stock market returns comes from either dividends (and buybacks) or the companies increasing ability to pay dividends (through earnings growth).
I'm not sure why you think having a place to live ( or to rent to someone else) is not productive... mind explaining?