We're all entirely dependent one things outside our control, and it's a worldview that's romanticized to the point of silliness to say anything else.

As for the land grant you're talking about, that's a huge, huge give-away right there; and, I'd note, in your hypothetical, you already inverted the sequence of events (be given land => you keep it, work hard => you get $250k).

All UBI does is recognize that, given how technological progress puts people out of jobs, we'd better find alternatives to distributing resources than what we do now, because we're going to end up with a lot of heads on spikes if we don't.