Every one of my travels to western states and every conversation I've had with other cattlemen there and elsewhere implies that it is exactly that. Perhaps once upon a time it was something else, and as the situation changed our government didn't keep up. I imagine that numerous bureaucrats at BLM and other agencies have some personal interests in the disastrous way that things are done. Some call this a "principal-agent problem".
Likewise, the various stupid wars we in USA fight aren't at all about our security or saving democracy or any of the other myths. Those are "UBI schemes" for armaments manufacturers and their employees in politics and the media.
"It can't just all be a UBI scheme for alpine beef ranchers, can it?"
As in, I wouldn't be surprised at all if it were, but haven't had the conversations you've had first hand.
I don't doubt at all the environmental destruction being wrought. However, the land's use is supporting some market for beef though, or else why would the question of $1 leases to stockmen exist?
Is it just that it's cheap and marginal (in both cost and quality) land that can be used for marginal production increases, or is it supporting some niche high cost beef sub-market based on its wilder place of production (high alpine beef)? It can't just all be a UBI scheme for alpine beef ranchers.