As a laymen, it seems to me that quantum theory is similar to the expanding universe theory in that scientists substitute complexity (cause of expansion, quantum states) with a token (dark matter/energy, indeterminacy) until you better understand the underlying systems.
The two examples you give are very different. I would argue that you are, indeed, very incorrect.
The purpose of scientific theories is to be able to make predictions about physical systems. Fundamental theories are based on some postulates (assumptions; in mathematics, we would have axioms). Quantum mechanics is based on a few postulates (which are expressed in very mathematical terms, like "Physical observables are represented by Hermitian matrices on a Hilbert Space H").
If the theory makes incorrect predictions, it is deemed to be wrong. If it makes predictions that cannot be explained using "common sense", then non-specialist come out of the wood work stating that it is obviously incorrect, that specialists simply do not understand.
For the expanding universe ... we have a theory (Einstein's Theory of General Relativity) which has been extremely well tested in all kinds of scenarios, and has always been found to make correct predictions. Your phone's GPS would not work if it would use predictions from Newton's theory rather than Einstein's.
The Theory of General Relativity can be thought as a set of 16 equations of the form:
(aspect of geometry of space time) = (stress-energy-momentum content of the universe)
In simplified terms, the left-hand side of these equations relates to the observed expansion of the universe. The right-hand side of these equations is what type of "energy/matter" we observe. We find that simply including baryonic (i.e. "normal") matter that we can see by looking (using telescopes) at the sky leads to inconsistencies with the observed expansion. If we include different type of energy/matter that we cannot see (i.e. dark), each obeying precise equations of state, we can have predictions that are consistent with what we observe. Thus, we use General Relativity + observations about the expansion of the universe to make predictions about what is the energy/matter content of the universe.
What you see as a failure, I see as a success of G.R. as it makes predictions about what is found in the universe which we did not know before, and had no way to know simply using the tools we had.
"Fun fact": many years before modern neutrino experiments nailed down the number of "normal" light neutrino species to 3, using General Relativity and known nuclear physics, one could use the observations of the ratio of light elements (He/H, Li/H, etc.) produced in the early universe to make the prediction that the number of light neutrino species had to be equal to 3.
> "Fun fact": many years before modern neutrino experiments nailed down the number of "normal" light neutrino species to 3, using General Relativity and known nuclear physics, one could use the observations of the ratio of light elements (He/H, Li/H, etc.) produced in the early universe to make the prediction that the number of light neutrino species had to be equal to 3.
Could you give a bit more detail on how the observatsions, plus nuclear physics, plus general relativity, led to that conclusion?
Look at the very short section titled Big Bang nucleosynthesis on https://en.wikipedia.org/wiki/Cosmic_neutrino_background. Based only on the relative abundance of He-4 and D (H-2), one gets an estimate of 3.14 for the number of neutrino species. You can find more detail on http://darkuniverse.uni-hd.de/pub/Main/WinterSchool08Slides/.... Basically, the more light neutrino species there are, the faster the expansion occurred in the early universe, and the less time there is for making other nucleus from protons and neutrons. After a while, the matter is to diluted for fusion to occur and the ratio of various nuclei is "frozen" .... until stars are formed much later on.
Can anyone tell me why I am incorrect?