Raising taxes is the only possible way a UBI would be feasible, and even then it wouldn't be a large enough amount for most people to live off of.
Also, a UBI is likely to cause inflation.
well inflation is equivalent to a flat wealth tax that doesn't consider insoluble assets, and is entirely in the hands of the government that imposes the UBI.
"cause increased prices for consumer/essential goods" is what you meant (since buying power is moved to people who are reliant on buying them), but this is a one-time transition to a new equilibrium (so is mitigable by increasing the UBI to account for it), not a constant ever-looming devaluator.
There is currently more than enough total production for people to live quite well.
If AIs simply replace people, the same total work gets done. It's just a matter of who gets the profits from it.
It won't be that simple, to be sure. Nonetheless we already produce far more than subsistence, and there's no reason why a UBI would change that. If it increases the price of some commodities because now everyone can buy them, I'm ok with that. It already horrifies me that some go hungry in the fattest nation in history.
I don’t understand why welfare is the answer. To me it seems we’ve super failed if that’s the case — just brings everyone down except a few ultra rich people.