This is an important point that frequently gets overlooked in discussions about the land promises in the Hebrew Bible. The land belongs to YHWH as the sovereign. The vassals in ANE treaties are given the land as a concession, holding it conditionally, depending on their faithfulness to the vassal treaty. In the case of some ANE treaties, the conditions are pretty harsh and so the vassals rebel—with predictable results under the Neo-Assyrians (hint: being skinned alive isn't my idea of a fun time!).
When looked at that way, the conditions on the Israelites are pretty lenient. Not that I would have done any better at living under it than they did. That is, if I tried to do it without the power of the Holy Spirit!