Nonsense. That is akin to saying "David Souter arrived on the court as a conservative but was so astounded to find that his ideology was not able to stand against John Paul Stevens' legal reasoning." The real issue is that justices do not always turn out like they were anticipated to behave. It was as true then as it is today.
As for Marshall, he had both his strokes of brilliance and his faults. He gave some good decisions and some bad ones including those that defied all basic common sense before him.
Marbury v. Maryland is a classic case of the latter. Arguing Marbury's side of what the constitution's enumerated powers were intended to mean was a young lawyer named Daniel Webster who, though reasonably intelligent, was not a participant in that document's drafting and possessed virtually no first hand knowledge to its intentions and meanings from the convention. Arguing Maryland's side was Luther Martin, who also happened to have been there in 1787 and actually helped to draft the very same words that were being disputed. He was also one of the convention's most active debators and knew the document it produced inside and out. So who does Marshall listen to and side with? Certainly not the guy who was there and could credibly tell you what the words he himself helped to write meant. No, instead he went for the loose constructionist interpretation offered by Webster.