Marshall also wrote that Marbury was entitled to the commission. He did not order Jefferson to deliver it because he knew Jefferson would ignore the order.
The Scotus is supreme among courts. It does not exercise supremacy over the other two branches and states.
The courts can question the constitutionality of legislation until the cows come home, but it only matters if the legislative branch accedes to the judiciary’s claims, and much more importantly, if the EXECUTIVE BRANCH is willing to enforce their opinions.Well, if you wish to believe that other branches of government are constitutionally permitted to ignore the opinions of the Supreme Court on the Constitution, that is all well and good.
But, that is not what Marshall had in mind. And, that is why Jefferson disagreed with Marshall.