Many things are possible, but that one would not on the face of it seem that reasonable. Dark matter _seems_ real hard to interact with in any way, pretty hard

Many things are possible, but that one would not on the face of it seem that reasonable. Dark matter _seems_ real hard to interact with in any way, pretty hard to harvest something you can barely touch. You could posit that they have advanced technology, but even so why wouldn't they use up their matter first? Why isn't there any other evidence of their existence? Etc.