The fatal problem with any universal basic income scheme is that people will always vote for whatever politicians promise to augment their basic income, irrespective of any other factors, leading to ever higher strain on the economy and eventually bankrupting the country.
Basic income is actually pretty rare, even among democracies. So it would seem you are empirically wrong. Not only will people not vote to augment basic income, they won't even vote for a modest basic income.
Few politicians have seriously proposed it so far. If and when they do, the votes will follow (a testable prediction.)
This process has indeed happened already. It was a large part of the downfall of ancient Rome. Glossing over the many details, when slaves were doing most of the work, people supported those politicians who offered them ever increasing grain doles, until the state could no longer afford them and collapsed.
Socialism in general is a variant of the basic income scheme, and hugely popular: a state guarantee of a certain basic income and level of material security, no matter what happens to you in life. It has done well in elections for a long time and remains popular today, as well as driving various popular Communist revolutions on a non-democratic basis.
India has 1.23 Billion[0] people in it, and that wikipedia article is quite short, with only 4 sources. They don't cite any of the sources for the figure which stated 6460 people are in the program.
The program serves %0.000005 of India, or in much more familiar terms, if implemented at the same scale in America it would help slightly less people than there were killed by lions in Tanzania over the trailing 20 years[1].
Sure, to be clear I would like basic income. My point was that it is really easy to raise capital and test it on a scale like this. While I was making a joke, the implications are real. Inflation can rise if people are all still buying things at the same economic level and region. Where does the money come from?
The problem with basic income is that when the conditions exist to make it possible, it wont matter anymore. We need large transition to solar, automated farming, automated transportation and distribution networks, etc. Then the marginal cost of food, transportation, energy will be $0 so we can afford to give it away.
Economics is not always the zero sum game it is made out to be. Microlending could work, and getting these people access to conputers and internet will too.
To be fair, that seems to be much of how it functions in richer countries as well. It's not as bad if you're well educated, have other strengths and a bit of money laid up. But if you're a minimum wage factory operative or warehouse worker or one of the other relatively unskilled low-paid jobs, then the thing that you're good at vanishing can leave you in a very hard place; very limited funding to retrain and limited options for doing so even where such funding can be managed.
If they are desperate enough to steal or riot, they might not be forgotten. Is imprisoning a significant portion of the population cheaper than a basic income or at least free provision of basic services?
I think we will boil as frogs too slowly for there to be a dramatic escalation of violence, but things obviously need to change.