That's not true. The border has always been open for people to pass freely for centuries.
Restricting border crossings would be a change in immigration policy. I don't think it's necessary.
And then we decided that having government, taxes, social programs, ect were necessary. You are free to feel otherwise, but the issue of society vs anarchy has been firmly resolved.
We already had gov't, taxes and social programs. It may not be apparent to you, but homesteading on indigenous lands was a social program. I'd love to see if you could make 4X the salary and 2X the quality of life by migrating to another country if you'd change your tune. I hope your rigid rules of society always apply to you and your descendants.
But I'm guessing you're ok with the folks who migrated to North America. Just not ok when those same people move around their own continent.
Moving towards an open borders would be changing restrictions on immigration.