The case of Marbury v. Madison established the concept of judicial review in the United States. If this case never happened, or if John Marshall was never made Chief Justice, what would be the long-term effects on the country?
It would have happened in a future case. Judicial review was lain out rather clearly in the Constitution, about as clear as you could get in those days without outright saying 'Judicial Review'.
The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority;
The right to strike down statutes which contravene higher law has always been part of the judicial Power and, according to the Constitution, the jurisdiction (the area where it holds supreme judicial power) of the Supreme Court is 'all Cases, in Law and Equity, arising under this Constitution', in other words, everything which ultimately relates to the Constitution, like Congressional laws.
Of course, removing Marshall entirely is an
entirely different matter. You irrevocably change the history of the US no matter what, but the direction that shift heads in is up to whoever replaces Marshall.