The fact that Uncle Sam is the ultimate rent seeker is beside the point.
The difference between land and widgets is that widgets are continuously manufactured and sold. Once you sell me a sandwich, you can't take it back. It's mine. Rent is the opposite. They're not making more land, or spectrum, or whatever, and that's not what they're selling. They're selling access to it. And they can revoke that access at any time. The thing I'm paying for isn't mine, it's still theirs the whole time.
The difference between land and widgets is that widgets are continuously manufactured and sold. Once you sell me a sandwich, you can't take it back. It's mine. Rent is the opposite. They're not making more land, or spectrum, or whatever, and that's not what they're selling. They're selling access to it. And they can revoke that access at any time. The thing I'm paying for isn't mine, it's still theirs the whole time.