It doesn't have to be that way. For one thing, you don't need to means test it. Just give the same amount of money to everyone. Then if you work you still end up ahead. So no dis-incentive to work. For another, if implemented properly the amount would go down if production declined, or up if production increases. This way it's self-correcting in the aggregate. As people leave the workforce, the UBI goes down, nudging some people at the margin to go back to work.

But this still leaves people free to choose for themselves, without interference from the government.