I'm working back from median household income in the US.
https://en.wikipedia.org/wiki/File:Median_US_household_incom...
I think the proposal's underpinnings are "lets pay everyone enough to live on, shrink all the complexity down to one number so we can all understand and impact what that one number is, and hope that those who produce for love of the game do so to an extent that allows us to keep the system running". Basically communism with a uber-capitalist kicker (slogan proposal: "Musk's gonna Musk").
From your comments, it sounds like you'd think that if we put 30k more per person on the table, the incentive to work would go away, and the poor are needed to work so it would break the system. Well, I believe we've already crossed this line with current entitlements and programs and there's already an advantage to not working.
This is a far right alt source so read it carefully and do your own thinking (could say the same for CNBC though!):
http://www.zerohedge.com/article/entitlement-america-head-ho...
In conclusion:
1. 3k is just another entitlement added onto a haze of entitlements.
2. The value would be a single number. We're giving it away inefficiently now, why not clean that part up and hope democracy/the light of day will bring a moderation to it. Likely not, but better than what is.
3. 30k would be a better number if all other entitlement of any kind were truly going away and we were going to truly play it strait up.
4. If I'm wrong on this and the number after cutting everything else off is really 8k or 10k or whatever, I'm still fairly skeptical we could pay for it.
5. I've focused a lot of my life on not being poor-ish like we were when I was a kid. I think I'm pretty disconnected from what that word really means, and intentionally so, but thanks for the reality check anyway. If you'd go into more detail, I'd read it. Specifically, say you were poor but wanted to make something, would the amount of money you'd need increase and by how much?