One of the purposes of the government or the militia is to protect the borders from foreign invasion. This costs money. A person that owns a million acres should pay proportionally to have his million acres protected.
There is no Federal Property tax now.
Would you tax those closer to borders more, because their land is more expensive to protect than Indiana or Iowa?
One of the few Constitutional tasks the Government is required to do (and has done without an acreage tax) is to provide for the common defense.
Otherwise, we could put on a Federal tax for living next to an Interstate Highway, just to fix the roads.
Whether taxes be collected through an income tax, excise taxes, fuel taxes, whatever, it is pretty much a given that someone with a million acres would spend more and pay more taxes than someone on a 75X150 lot, just taking care of the place, and it is far more likely they would be producing food, minerals, oil, coal, timber, or any of a host of other products on their land--all of which at some point would be taxed. So the assumption they they wouldn't be paying their "fair share" is bogus.