[ctdonath]

Because relocating requires a tremendous effort: new housing, job, occupation, acquaintances, etc.

Because a lot of that cheap land is cheap for a reason: low/no data service, harsh weather, insufficient community.

Because "basic income" is free: the whole point of UBI is a basic income which one can get by on - non-zero effort to work at all withers against the prospect of being comfortable doing nothing; there is no imperative incentive to work.