Obviously squatters are an issue but if you have excess land than what you and your family needs to live and grow food then you could very well rent out your land, obviously not for money, but some other service, helping out with the farm, defence of land. A feudal agreement of sorts. Of course if no one respects your property, and are willing to kill you for it, then no commodity is better than any other. Even guns, you're just one person.
Let's take your clean slate example and pretend that the lower economic class somehow prevailed. I would assume that under this outcome, the lower class, in order to limit or eliminate the power of the wealthy would engage in redistribution of said wealth. Initially it would be the common useful items that would be highly prized, tobacca and hummel (I'm assuming you mean barley). Throughout this time, I think gold would maintain its value, however the value of acquiring basic necessities would overshadow gold's value. As time went by and the economy began to stabilize, I think the value of these common items would drop in comparison and beautiful things such as gold and silver and diamond would become highly desirable again, and in vast quantities. Gold is pretty. We like pretty things even if they're not useful. "Everything is worth what its purchaser will pay for it." ~Publilius Syrus And humans will always pay hand over fist for gold.
True. I had a very odd dream last night: My wife and I were browsing in a shop that had a bunch of oddities, and I found a bin of branches. I picked up a branch and heard a rattle. Breaking the branch, I found an old tin was inside. I showed the store owner, and he opened the tin. It was full of gold rivets. We Googled these rivets somehow, and found they were made in the late 1500's and were 40% gold. -Such a fucking bizarre dream. Anyway, my subconscious finds gold to be of value, even if its sense of history is fucked. :) I don't see everyone waking up an agreeing that gold is essentially useless. It's more than its rarity, too. It doesn't rust, and it can't be easily destroyed. Once you have it, you have it. All that said, I don't see an apocalyptic calamity on the way. Lot's of people are going to be out of work, and maybe some governments will get a new face, but we'll get through this. Land is good. As the saying goes: "They aren't making any more of it."