There are a couple of ways you evade the point in saying this. I'm not familiar with all of those systems, but in general they depend on a social contract to assign value to weapons only if it is reasonable to agree that they are assets within the setting. Thus, if you were trying to run a non-comic game, but one with a certain seriousness, you'd not have a die or trait assigned to the possession of an object which lacked utility as a weapon and in general the story teller would rule by fiat that that trait generally didn't apply to declarations of intent to do damage. Certainly within those systems you could declare things like 'Beware my Rubber Chicken' gave some advantage in combat equivalent to "I love my trusty shotgun ole Bessy." but the point is in practice players know not to do that and game masters don't respect attempts to violate the setting guidelines. Thus, holding a bazooka in Cortex Plus might generate an extra asset die in a way that holding a rubber chicken would not, or having a sword might create some advantage in a fight that holding a limp wet noodle or a bundle of clover didn't.
However, in such systems you are highly reliant on the game masters to respect and interpret the mechanics in light of the setting supposedly being emulated as the rules themselves aren't actually doing the job of genera emulation.
Well, the only one of [MENTION=42582]pemerton[/MENTION]'s four suggested systems that I play a lot is Heroquest, and that is pretty specific about abilities, and defines what happens for ones where you're using a broad ability, a defined ability for it's intended purpose, or an ability that it's a stretch to explain how it interacts with the situation. Does that require that the GM and players accept and understand the constraints of the setting? Yes. I'd suggest that if you don't trust the "social contract" in that sort of game, then you can't really trust it to control the excesses possible for spell-casters in D&D and that has implications for the importance of balance too. Perhaps the biggest being not to play with <people of manner undesirable>.