Except that there is empirical evidence which supports the existence of the latter three, at least to a certain degree. I will agree that there are issues with things like dark matter (which I'll focus on), but the astrophysics community is already well aware of those issues. For example, why is it that you think so many physicists are attempting to directly detect dark matter particles in laboratory experiments? They are trying to detect these things (be they WIMPS or whatever) because they know there are a lot of people, like me, who think the dark matter hypothesis is probably the best thing we have going now, but it cannot be considered truly solid until we detect the stuff directly. The history of how neutrons & neutrinos were proposed theoretically and subsequently detected by direct experimentation is, I think, an excellent analogy.