I think there's some kind of fundamental disconnect feeding this argument that needs to be resolved.
There absolutely is. Namely: you have no comprehension of how national development actually works.
Remember- Avalon is going to lack "seed" governments. They won't be able to go "hey, look, the British own this land" or what have you. They'll be starting straight out of the Stone Age (only vastly accelerated). There's a reason it's called "city states"- because that's the model of government *used* back before countries were a real thing.
All nations created on Earth- or Avalon- start, functionally, as self sustained colonies intent on producing something of value for trade. Or, sometimes, just as a middle finger to others and a plan to be truly self sufficient.
They also tend to start as populations less than a couple hundred.
... A couple hundred people can *easily* be sustained by the "natural" environment of Avalon. Or, for that matter, it can be sustained with a few large farms that would in no way not fit in that starting colonial grant.
From there? They build. After a certain level of population, it becomes mathematically impossible for them to sustain themselves, and they MUST seek outside trade. So if they wish to remain truly independent, they can't go above a certain population limit. Same as in the real world.
So. Yeah. Buy it or make it yourself. If you make it yourself, you're using your own land to do it. Don't have enough land? Get more communities to join yours. Because, unlike in real history, you do not have the option of taking it from your neighbors by force.