UBI in a world where everyone makes roughly the same amount of money per year would be a wash. You'd just be redistributing money to people in roughly the same percent that is was taxed from them. But we do not live in that world.

And even if it does end up as a complete wash, that still seems like it would lead to a better economic outcome. You'd end up with trickle-up economics. The kind that has incentives for companies to appeal to consumers, and consumers that have money to spend on goods and services.