That example seems so contrived that it's difficult for me to see it representing reality in a meaningful way. It may be too simple to be useful.
In reality, that tenth widget still gets produced. They hire someone else to replace the "UBI recipient" or else run the production line slightly faster so nine people make ten widgets, or else automate and fire all ten employees, and make twenty widgets a year. Nothing in a real economy is that zero-sum. Value which only exists in potentia and which may as well be created by other means cannot reasonably be said to be "destroyed." Something which never existed can't be destroyed.
UBI just decouples a person's ability to work with their ability to live at a subsistence level, it doesn't prevent them from working.
In reality, that tenth widget still gets produced. They hire someone else to replace the "UBI recipient" or else run the production line slightly faster so nine people make ten widgets, or else automate and fire all ten employees, and make twenty widgets a year. Nothing in a real economy is that zero-sum. Value which only exists in potentia and which may as well be created by other means cannot reasonably be said to be "destroyed." Something which never existed can't be destroyed.
UBI just decouples a person's ability to work with their ability to live at a subsistence level, it doesn't prevent them from working.