You don't "own" your yard any more than the squirrel in your yard "owns" it. Ownership of land is just a government acknowledgement of what property you pay taxes on and what property is designated as your own. Ownership of this type is a human invention.
As for "just waiting for someone to find it and claim it to get rich off of it", this clearly views the world in a mercantilism way. However, this is flawed because not all resources are limited. Renewable energy is a good example of a resource which isn't limited. Your perspective also incorrectly assumes that the goal is to "get rich off it" but there is also much value in friendship, connections, harmony and many other values than just how much money is in your bank account. For example, you can't buy love.
I’m pretty sure every single cow is owned. There aren’t wild cows. Every single bit of land is owned. The squirrel in your yard doesn’t even realize it’s trespassing on land it doesn’t own. Oils been on earth millions of years and that’s all owned now. It was just waiting for someone to find it and claim it and get rich off it. All the trees are owned-you can’t just chop one down. The earth was around billions of years just waiting to be owned by humans. Rich people look into the sky and realize how much is out there they don’t own. Inspiring. Life is short so try to own as much as you can, because it’s hard to own stuff when you’re dead. Good luck.