I have visited perhaps a dozen automotive museums in the US. One thing I feel they uniformly lack is any technical exhibits about the cars. That is, bodies off frames so you can see the chassis layout, descriptions of innovative suspension systems, engines on stands with explanations of how they advanced the field, etc. I find aviation museums do a much better job at this. Perhaps being a scientist I am biased toward the technical, but I feel a mix of the beautiful and the technical makes for a more satisfying experience. These are, after all, transportation machines. In contrast, I found the Computer Museum in Mountain View, California mixed technology with beauty (yes, beauty) very well.
A good technology museum should be equal parts art museum and science museum, two types of beauty in harmony.
My guess is the high visibility museums are run by museum professionals (ie., those with humanities degrees) and not by technical people (engineers, mechanics, pilots, etc.)