It's not a matter of snapshot view. A pulmonologist has a snapshot view too.
It's (as I explained earlier) looking at the right thing or not.

My pulmonologist looked at my endurance (after he realized my respiratory tests were all over the place), whereas the neurologist looked at my momentary strength.

Ironically, the endurance test was done because a neurologist who recommended checking my lactate level during exercise (due to a false positive result on another test), and my pulmonologist said that in that case we will do a more elaborate test which will give us more answers than just the lactate levels. (which were the only parameter which was completely normal in my tests!).

The other respiratory test was done because a neurologist told me with confidence that I require respiratory support because it provides psychological relief. I told him that I am fine with that, but would like to have a more accurate assessment of my respiratory status before I seek psychotherapy to help me get over this ridiculous need.

Upon receiving the results of the respiratory tests he told me that I have a rare form of MG (he himself nearly missed) with significant respiratory muscle involvement and that he fully agrees with the pulmonologist that I should keep on using my respirator.

The same neurologist decided I was in remission, because a repeat sleep study done with respiratory support showed significant improvement (as compared to the previous one which was done with no respiratory support).