If you want to consider just social assistance then the US government spends about $950B annually, and that works out to $2800 per year per citizen. To make it a livable amount you'd have to at minimum 5x that expenditure (and a lot more than that in urban areas).
By the way, I think you're overlooking the strongest criticism of my UBI proposal: that it would reduce the incentive to work, potentially lowering labor participation and, in turn, government tax revenue, which could make the system unsustainable. It's hard to predict whether that would be a real problem or not.
It is such basic economics I just can't believe we even have these debates.
It is something I would have thought of when I lived with my parents as a clueless teenager.
There are many countries around the world where that would be normal, or even a sign of affluence.
The other benefit of raising taxes is that it will control inflation.
And $13K/year isn't enough to live on, yet many disabled people do just that. 4 people each getting $13K can probably live together on that. Living alone is a luxury.
And with UBI, there are no limitations on you supplementing your income on the side. One of the biggest criticisms of UBI is that everybody will stop working. If UBI is $13K/year pretty much only those who are unable to work will not supplement their income with work.
To me, it is a non-starter unless you also had a massive housing build out to drive the cost of housing/rent down. We can't do that now though so that is also a non-starter.
Then even if you did massively build out housing, most the UBI will still be captured by rent/housing as some areas will become extremely low status and people will use the UBI to move to higher status areas.
All UBI really does if everyone gets it is change what $0 means. Not to mention, if you replace what people are getting currently from the government with UBI they are getting totally fucked. People on disability would get completely fucked since they are getting a basic income now but even though the UBI would be more in total, that will just purchase much less if everyone is getting the same amount.
I'm not the type of person who blindly supports UBI. I think that it would be disasterous to implement it without rethinking how the economy should work and how UBI is going to address social woes. That said, I do think that it will be necessary in the long run. Money, may it be earned or granted, is a tool for people to make decisions. Traditional social programs pretty much does the opposite. It removes autonomy. It removes accountability. It doesn't much matter whether it is social housing (something physical) or conditional grants of money (which is a major focus of this article).
Or, if the UBI is insufficient, you could work or move someplace less expensive.
Most anything else would feel unfair (as a result of being so) and tend to drive a cycle of inflation in the expensive urban areas rather than working against it.