"If it's not implemented that way, then the inevitable result of UBI is simply inflation."
Exactly that. Money, when working properly is equivalent to some sum of goods and services. Money without that backing of good and services is just inflation.
But USA is so afraid of anything resembling "communism" even in the slightest that something as obvious as that simply can't go through their skulls. You can tell that quite a lot of countries are half way there, as they already have socialized education and healthcare, with the result of lower social and economic inequalities and a healthier population with longer live expectancies (on top of all that which is already socialized everywhere so they don't even notice like defense, social peace, justice, etc.), so it's "only" a matter of adding food and shelter to the equation -they still will say something like that is utterly impossible.
In other words:
"Do We Need To Plan For a Future Without Jobs"
"And Should We Resort To Universal Basic Income?"