In science failure can be a success. Finding what doesn't fit an hypothesis can be movement in the right direction, by reducing the number of possible variables. Of course, such "progress" assumes your hypothesis is where truth exists.
In other words, getting closer to being really lost is not always better than simply being lost. Ultimately, as Socrates said: "The only thing I know is that I do not know."
Modern scientific technology assumes that somewhere out there an experiment, or experiments, can prove or disprove every physical thesis. Whereas this may be so within the range of our ability to measure and verify through multiple ways, what if the elusive answer is beyond our measuring technology?
The most interesting stuff in cosmology starts with the word "dark." Be it dark energy or dark matter, that "stuff" is far more abundant than the baryonic matter we can see. It is assumed incorrectly that dark matter is not the same as dark energy, and that dark energy is a greater part of our universe than dark matter. What's left seems almost incidental, except that this visible universe is what we call home.
Physics involves the equation of matter and energy, and their mutual interchange. We can measure down to nano dimensions, but not nearly far enough down to get to the essential components of dark matter/energy. This leads to such detours as defining Higgs bosons and WIMPS as fundamental particles, when they are not. We cannot honestly fit all things measurable into our measuring machines. Therefore, that which is beyond measurement appears to be metaphysical, not physical.
Much of today's cutting-edge physics was yesterday's metaphysics. And tomorrow? Some of today's physics will join tomorrow's metaphysics. After stripping away false hubris, we can learn to live with higher quality metaphysical theses, combining honest philosophy and advanced technology.
All of which brings us to massively funded Snipe Hunt #2: the search for WIMPS, weakly interacting massive particles, possibly the essence of dark matter. (Snipe Hunt #1 is the hunt for another non-fundamental particle, the Higgs boson.) The famous LUX (Large Underground Xenon Detector) experiment has totally failed to find WIMPS, but there is hope that a souped up version of this experiment might reveal something. Nor has any other experiment found any verifiable WIMP activity. Mind you, this is for something that is supposedly far more common than ordinary matter. Gee, could it be that the basic hypothesis is wrong? Not to worry, there appear to be millions, even billions, of dollars ready to pour down both snipe holes.
Plain and simple, these experiments are not looking at the real fundamental component of dark matter, and even dark energy: gravitons. Most people think gravity is the weakest of the four fundamental forces. However, gravity can be the strongest force. It is also the fundamental force, so that there is a GUT, or grand unified theory, to be built around gravitons.
The thing about gravitons is that they are smaller than any way to directly measure them individually. They are in the size realm of hypothetical strings, and far smaller than any pseudo fundamental particle. We're talking 10 to the minus 37th power meters. Indeed, other so-called fundamental particles are much larger and composed of myriads of gravitons in ways we don't yet fully understand.
An understanding of curved space, and of the simple law of gravity (both taken to the smallest dimensions), gives us conceptual tools to see mentally what we cannot verify physically.
On the other hand, the neat thing about dark matter on a macro scale is how it measurably interacts with massive structures that we can see. From these verifiable observations we can begin to build an hypothesis worthy of respect.