Has it ever occured to anyone in the USA that your
country is just too big to manage as a fair democracy (in terms of
people numbers not land mass) and maybe the whole federated states thing
is becoming tricky to manage?
The US constitution does not charter a democracy per se. It establishes a federation of states, each of which is a republic with elected officials (not a pure, direct democracy). This is to temper the passions of the moment, reducing the opportunity for tyranny where a slight majority can oppress a slightly smaller minority. Reflect on our recent elections, and you can appreciate the wisdom of this. Congressional "gridlock" between House and Senate is not a problem with our system, but a feature: distribution of power so that no one part of the government has total control (except, perhaps, the IRS!).
Fairness is in the eye of the beholder. That is the reason for limitation of government powers, and for subsidiarity: making government decisions at the most local level possible, not by bodies far removed from those the decision affects.