Realistically, in the short-run, basically the same people doing it now: even a "just out of poverty level" UBI isn't yet sustainable with the current level of productivity and automation. So, the people that can't get a better job than lettuce picking will still need to work, and will still be picking lettuce. They'll have slightly higher total income. (From the UBI itself; whether their wages will change and in which direction is less clear.)
> What does that do to the price of lettuce?
Not a lot in the short run, though maybe small increases.
> If we apply that same thinking to every other food item, what does it do to food prices?
Likewise. A "mature" UBI that would be at a level that would substantially change this would also require levels of productivity and automation where you probably wouldn't have people picking lettuce (though you'd have a few maintaining the lettuce-picking bots) in the first place.
Fundamentally, 'value' (goods, services) is produced by someone and consumed by another. We all trade our efforts. UBI is trying to enable consuming without producing at some level. But it only works if someone (or something - robots) are producing without consuming. Right now the working poor are filling the role of producing more than they can consume, which is not right. But someone/thing has to do the producing, and more cannot be consumed than is produced.
A mature UBI (one that can provide an out-of-poverty level benefit) requires more automation and productivity than we have now, but that's not "robots doing all the work".
> I don't think a lot of socialists see that
Most UBI supporters aren't socialists, and many (possibly most) socialists aren't UBI supporters.
> they seem to argue (like in the original article) that we should be able to move that way now.
We can certainly adopt a UBI now, and there are arguments for adopting a low-level UBI that increases with productivity (perhaps "automatically" by tying it to a dedicated tax, or share of an existing tax, that is naturally tied to output growth) as the way to get to a mature UBI.
> Fundamentally, 'value' (goods, services) is produced by someone and consumed by another.
Yes.
> UBI is trying to enable consuming without producing at some level.
Not really. It has the effect of allowing some people to consume greater value than is indicated by the payment they receive from others (not considering the government). In some cases this may be consuming without production, in others it may be people that you acknowledge are already producing more than they consume getting a correction.
And note that it replaces existing systems which already do this with various inefficiencies which it seeks to eliminate.
No, that's you just making assumptions. It's not one thing or another.
Goods and services are finite, and at the level of a society/world/country are being consumed at the level they are produced (notice we don't have warehouses continually filling decade after decade of anything). UBI means everyone would be able consume more than they are now -- it doesn't matter what they consume, but it would be more. And it might allow some that are producing to produce less (work less). That imbalance can't exist for very long at all until prices rise to get back to equilibrium. There's no way around it.
The administrators of the current welfare system, that currently costs us more that UBI would.
If the prices of things are being kept artificially low, due to the duress of the employees producing it, then the market will fix the problem. We might see a short term rise in certain commodities. But, unfettered, this just induces more efficiencies, such as automation, into the system. Efficiencies produced by upper middle class engineers, who would now, thanks to UBI, have the same earning power as their upper middle class parents did.
UBI isn't wage inflation for many reasons, such as the actual value of money isn't equal to people with different incomes. It isn't going to become more expensive to live, because people don't go out and buy twice as many groceries when the have twice as much money - the money is used for different priorities.
More money chasing the same goods increases prices.
Imagine each family has $15K more than they do now. Some would upgrade their living conditions, causing more competition in the strata they are moving up to, which would increase prices. Some would buy cars they couldn't previously, causing more demand for cars, and increasing prices. Some would go for luxuries they couldn't previously, causing more demand.
There is no way around supply and demand.
The only way prices don't increase is if demand doesn't increase. If some people create more demand, others have to have less demand.