GK121/Engines -
An issue with both the F-35 and the V-22, from the Marine viewpoint, was that the service bought into two false promises.
One was that, because of multi-service commonality and a consequently large buy, they could get the extras - stealth in one case, tilt-rotor speed in the other - for no extra money.
The other was that the extras would be delivered with no schedule risk or performance compromise.
In the case of the V-22, the other services walked away and continued to buy helicopters, leaving the Marines with an aircraft that (most of the time) is an expensive helicopter.
In the case of the JSF (and here is part of KBrockman's answer) the rest of the operators are stuck with a compromised design (for example, short, broad body, complex structure, small wing, heavy and expensive engine) while the Marines have an aircraft that is expensive to acquire and operate and marginal on bring-back.
Historically (to address GK's point) there was a time when a small jet force on the MAGTF was the answer to a lot of scenarios - little if any air opposition and no threat to the ships - and the AV-8A/B was never that expensive of a program, in absolute and relative terms. It was also small enough that forward/austere/going ashore ops could be contemplated.
F-35B is a lot more money. (If the Harrier had cost more than a contemporary CV fighter it would never have been contemplated.) It's a lot more demanding in terms of logistics on land (no 1000-foot runways are being talked about, GK). And the likely opposition will not be headed by a squadron of rusty MiGs, but will range from insurgent rockets and mortars and counter-logistics operations to MANPADS, mobile SAMs and sea-skimmers carried on trucks.
Hence the question: Where's the scenario that calls for a few F-35Bs?