The Gauls were basically genocided by that. Property rights are really just a record in a court house. When Rome collapsed those land rights lost consistent authority and so there was no reason to think long term. The Germanics who land rights system was based on their own customs maintained a meaningful economy and expanded into the areas that were economically disfunctional.

Historians over consider war, because they want events to think about. The standard narrative of the German displacement of the Gauls is that the Huns were expansive so the Germans went west. Maybe it has some truth. But it doesn't explain why the Gauls were so easy to displace, when the Gauls had dominated Western Europe for millennia. Now Gailic people are a relative rarity with a few pockets of them here and there. So weak property rights can literally genocide people.