[comicjk]

Indexing UBI to a revenue stream is a bad idea because the revenue will tend to swing up and down in sync with economic cycles, making bubbles frothier and recessions worse. Constant spending by contrast acts more like an automatic stabilizer. https://en.wikipedia.org/wiki/Automatic_stabilizer

[dragonwriter]

Indexing to revenue is a bit of a simplification. what I really think is the revenue stream should be split between current benefits and a reserve fund, with the reserve fund drawn from to avoid decreases in cyclical downturns. The idea is that the long-term effect should be increasing benefit with productivity, while avoiding short-term benefit drops.

And the effect you describe is really one of overall domestic spending, not one program in isolation.