Otherwise we have Great Depression again, when there was a lot of production, but public simply didn't have any money to buy it.
The solution last time was to basically distribute money to poor, e.g. fund mega-projects with tax money. I feel like UBI sounds pretty much like that as well.
...why again do you need customers?
Mass infrastructure investment would be great, trouble is we need educated workers now, not day labourers, so we need to combine the infrastructure building with education both formal and on the job, ideally at a part time rate, say 3 days a week
I never thought UBI meant communism. If you want more out of life, get a job that pays over-and-above UBI.
The more likely outcome is that prices on a whole lot of things are about to drop drastically. Of course this does nothing to help the people who are left out of a job and can no longer contribute as they are no longer cost-effective. UBI is one option to address this, at least partially. Do you have a better one? Ban AI? Do you happen to be an anti-capitalist, and your convenient solution is (big surprise) to remove capitalism as an economic system?
I'm not saying the effect of more people being outcompeted from the job market will never be a problem. Perhaps parts of it will be solved with income redistribution being increased. Perhaps part of the effort will be in creating new jobs where humans can not be replaced. Some cookie cutter "anti megacorp" rhetoric ain't likely to help much.
Seriously, if you have that kind of power, what's the incentive to let everyone else live?
Ethics and morals, maybe? Basic human empathy? I think I get where you're going with this. There are those, sociopaths and psychopaths for example, who would go to any length to get that kind of power and... what, when they have their T-3000s they're suddenly gonna have a come-to-Jesus moment? Unlikely, yeah.