Nice idea but I doubt we will see it happen any time soon, far too much hatred, selfishness and greed for anything like it to emerge.
Take the United Kingdom for instance, (we should now spell the United part with a smal 'u,') A country that you could fit into Texas a couple of times and yet here we cannot agree about a political party to lead us, Scotland and Wales are demanding their independance and already have their own language and we could als o toss in Irish and Cornish to the mix.
If it ever happened what would you do with all the armed forces no longer required, the arms dealers and border officials.
You would have to legalise everything because you wouldn't be able to control anything.
As for one religion... you have one lot waiting the second coming, another lot still waiting for the first coming, while a third lot think he's been and gone... so don't hold your breath !