I think it's more that I'm looking at the quantitative track record of scientific theory in general rather than the data on dark matter specifically, and I see how that's probably a mistake. Ultimately any theory has to stand on its the merits of observation supporting it rather than be tested against the collective success of past theories. Not only is its validity independent of theirs, but since much of the exercise is reducing areas of known inaccuracy, it's easy to cite a mountain of disproven and/or modified theories that don't prove much except the limitations of mans intellect and knowledge, which is a motive rather than deterrent to further research. Most people aren't researching proton decay because it's increasingly untenable--but research continues regardless, which isn't a bad thing in itself, so long as it does become an END in itself, in defiance of evidence. Other than a GUT as old as I am, what GUTs DON'T require proton decay?