Ah, so that’s what all those questions were about… Smart move on your part!
Yep, the two players in question were definitely not into the game. Shame that, since John Carter really is a remarkable game in so many ways and offers a somewhat different take on the sword & planet genre because of its style and feel.
Damn, but that is a lot of Threat! I don’t think in any game session I’ve run with the raw, even at conventions, that I’ve had such a high differential in Threat from the start of the session (the 9 to start and 20 later). Interesting dilemma, to say the least.
Those Difficulties don’t strike me as all that tough, so the fact that the dice were just rolling badly for the players is just someting that you had to roll with (so to speak).
Yeah, I suspect that their doing nothing outside of combat was part of the problem. Non-combat tasks are a good way to generate Momentum usually, 'cause the difficulty is usually D1.
Like you, I also assume the rule was put in there for a reason, but to be honest, I think I prefer the game with no limit on how many actions in combat you can spend Momentum on. Of course, if the dice are rolling poorly, then the point becomes moot.