I asked the exact same thing and my post got flooded by downvotes and accusations of being a bot.

I summary, in game theory terms this is like the prisoners dilemma game. Everybody acting in a selfish way ends up being the worst scenario for everybody. UBI will never be implemented as there will be no motivation to do it or if it is implemented it will be terrible for people to depend on other's productivity to live. That gives a complete power over your life to the one that feeds you. Similar to any communist regime.