Earlier quoted context omitted.
Universal income covering the very basic would still keep people making beyond minimum wage vulnerable. Paying meaningful money would be too expensive at scale. Then few jobs could pay meaningfully more than the universal income. Why work if you get +/- not working?
Your understanding of universal income is broken. Everybody receives a monthly income, regardless of them working or not. The incentive to earn more by working is always there.
What would really happen is they would raise their prices to earn the amount of profit they deem necessary to be worth the trouble of being in business. Everything gets more expensive, and the UBI payments won't be enough to live on.