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.
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.