History and theory suggests that the problem of how to account for dark energy (the accelerating universe or the increased stretching out of space itself) may be a conceptual reference frame problem.
From a historical perspective, physics has sometimes been stymied not by difficult mathematics but rather by taking for granted a conceptual point of view that must be varied or even inverted to arrive at a more successful theory. For example, the Earth motionless relative to the revolving Sun, consistent with ordinary quotidian perception, turned out to be less effective as a conceptual reference frame than the Sun motionless with the Earth rotating. The rate of change in time as an invariant was a hurdle in the way of explaining the invariance of light speed in a reference frame orthogonal to the passage of the Earth in its revolution around the Sun. So there are historical precedents for theoretical difficulties not being mathematical but rather the point of view.
As to theory, modern physics has general relativity and a considerable body of physics related to it, astronomical observations obtained using advanced telescopes, CCD’s and other technologies. The resistance of dark energy to a solution despite the available mathematical, technological and theoretical physics suggests that the possibility lies not with the problem solving tools available but rather an inopportune choice of conceptual reference frame. What are your views?