The obvious question you have to ask here is why that's not happening. And the answer there is that the government serves the interest of the ruling class which is the capital owning class. People with significant amounts of capital pay for political campaigns, buy up media, do lobbying, and thus have far greater say within the system than regular working class stiffs. Also, note how the working class has practically no representation within any western political parties. So, even individual interests of the politicians are aligned with their wealth patrons rather than the working majority.
The other problem here is that UBI can be easily gamed where companies simply adjust their prices to account for basic income they know people have. A better approach would be to provide universal basic services where people have guaranteed access to basic needs. Of course, that would require state run industry to provide those services. At which point we need to ask the next question which how this system would be better than a combination of state owned economy and worker run cooperatives. In the latter case, state run industry would be responsible for providing these basic services, building infrastructure, and managing other cross cutting concerns like energy production, and food security. Meanwhile, worker cooperatives would fill the same niche as private enterprise does under capitalism, except they wouldn't suffer from a problem of the wealth being concentrated in the hands of people who own the companies. It would go directly to the workers and circulate back into the economy.