I do want to believe all of that, but I am also not going to underestimate the tendency for de facto oligopolies like ISPs to continue colluding on prices, or landlords disproportionately raising rents to "keep out the (probably non-white) poors" who have been gifted greater economic mobility.

I'm just not keen on any policy which assumes that the market can be trusted to course correct itself in a way that is healthy and fair for consumers, because that is so often not the case. I would honestly prefer a system with no UBI, where people simply do not need to buy basic necessities at all. Shelter, food, and utilities should be fundamental rights that people shouldn't need to pay for in the first place, and income would just allow people to improve the quality of those things should they desire.