I have already addresses that, read the whole thread. "To "establish" post offices and post roads is only the authority to decide where post offices would by constructed by State governments or the people and along which routs the mail would travel. "To establish" is no green light to finance anything. It's only the power to 'decide."
That's simply your own definition. Since Section 8 is a list of FedCo's responsibilities it is clear that those responsibilities are ongoing.