In The Expanse, the main reason for complaint from earthers seems to be caused by overpopulation which leads to difficulty in obtaining realestate and the benefits that landownership brings.

If UBI was implemented as in The Expanse (food, shelter, and meds are free), I would expect the population of the earth to plummet. The UBI would allow for more people to pursue learning and educating others. It has been shown that when people feel safe from threat of violence and starvation, and when they are more educated, the desire to breed decreases.

On the flip side, perhaps knowing that you are off the hook for paying for the expense of many children would increase the desire to reproduce?