I am not a physicist, but I think it is not. It seems they can account for mass in various places in universe, they can model how things should be moving (bein

I am not a physicist, but I think it is not. It seems they can account for mass in various places in universe, they can model how things should be moving (being affected by gravity), they can measure how things are actually moving and from this they can infer where this missing mass actually is placed. This is currently all pretty early stage but the resolution is expected to increase with time. So no, I don't think dark matter is an epicycle. It is more or less like the case of gravitational disturbance affecting planets in solar system and somebody theorising a planet placed somewhere would explain the effect, we just can't yet measure things accurately enough to tell where the planet is exactly.