Engines,
You are absolutely right as to the Marines as a combat force. And I hold them in great regard for such efforts as their use of ScanEagle UAVs.
However, their record in the driving seat of MDAPs is very different. V-22, EFV and F-35B are classic examples of overloaded and compounding requirements: Fitting a tilt-rotor on a narrow deck; 20-25 knots in an armored vehicle, demanding a hot-rodded tank engine; stealth + STOVL + supersonic.
Have you asked the basic question: What is the scenario in which you require a stealthy, multi-sensor, supersonic fighter, but don't also need the AEW, EA and ISR that the carrier air wing includes? Because that's the only kind of scenario where F-35B (for the US) does more than add a handful of jets to the CV's 50-some.
I asked Amos that, in public, and got no answer except the usual talking points.
Also, the Marines and Navy have never managed to sort out the problem of supporting much heavier and complex aircraft (JSF replaces AV-8B, V-22 replaces CH-46, CH-53K replaces E) on the same size ship. LHA-6/7 dispense with the well deck, with more aviation space and fuel capacity, but that has been ID'd as a mistake and LHA-8 and subsequent will revert.