I sort of see what you mean, but lease prices are typically 1/2 of a percent of the land's value, or thereabouts. That means if the landowner didn't cut timber it would take 200 years to pay off that land, not counting interest. I think leasing land is a much better deal vs buying in some situations, but not all.
At the end of the day, there's more people and not an acre more land, and that drives prices up.