Pretty close, but the words that I have heard are closer to: ‘We can’t find any other explanation, so it must be true.’

Your example reminds me of a time when a company I was on the Board of Directors of had floated some bonds in order to do seismic upgrades to the buildings. The bank underwriting the bond only allowed us 80% of the bond money raised, and the other 20% was held in something resembling escrow, just in case we were unable to repay the bonds, so that the bond holders would still get something back. Thus, while the stated interest rate was one value, the real interest rate was somewhat higher (would have been 25% higher, but the “escrow” paid some amount of interest).

I think I have a slight idea of how the universe must be feeling, if it can only use 15% of its actual matter. What a waste of 85%.

Unfortunately at the scale of galaxy clusters it appears there may be a need for Dark Matter or another version of gravity beyond MOND, and the CMB together with Big Bang Nucleosynthesis suggests that there must be more matter in the universe than accounted for by baryonic matter.

At least, all of that is my understanding – this is an area of interest for me but I am certainly not an expert. Personally I suspect that the CMB interpretaions and other aspects of cosmology are in need of correction, but the question of course is how.

When I protest that my checkbook indicates I have $1000 in my account, they say “Oh, you DO have $1000, but $200 of it is Dark Money that you can’t use!”

When I ask to see my $200 in Dark Money, they say “Nobody can see it.” When I ask how then they can know it’s there, they patiently explain that since my checkbook and their records both agree that I have $1000, but we can only see $800, this proves that there is $200 in Dark Money in my account!

This is also exactly how they “prove” that Dark Matter exists!

Where the various theories differ, is in explaining what exactly has happened since then. And how does gravity work?

So I don’t think it is correct to call MOND (for example) “skepticism of the Big Bang”. More properly you could call it “alternative theories of gravity” or perhaps “an alternative model of how the Big Bang worked”.