That’s why I picture it as similar to an insurance program, like crop insurance.
No individual farmer can guarantee that he will have a successful crop in any particular season. But the aggregate of all of them is bound to be successful.
So every successful year, you’re paying in twenty percent of your growth. On unsuccessful years, you’d have less growth.
With the surplus, the “government” arranges to pay “workers” who will earn their bread or its equivalent doing public works. Overall, every person involved on either side should be working for the common success of all.
Try to make that scheme work!
If there is a way to make it overcomplicated, insane, and unwieldy, government can make it happen.