Goods and services are finite, and at the level of a society/world/country are being consumed at the level they are produced (notice we don't have warehouses continually filling decade after decade of anything). UBI means everyone would be able consume more than they are now -- it doesn't matter what they consume, but it would be more. And it might allow some that are producing to produce less (work less). That imbalance can't exist for very long at all until prices rise to get back to equilibrium. There's no way around it.