Your entire argument falls under when you take into consideration that the very judicial power that's "vested" to the Supreme Court in its jurisdiction is solely delegated to Judges that Congress appoints.

Congress should not get to seat its own checks and balances, and it doesn't particularly matter if Congress is only allowed to establish and ordain inferior courts to that of the Supreme Court, if they already effectively establish and ordain the Supreme Court's delegations - and thereby its power.