I will have to agree that the Stradivarius is a singular instrument. I have been stopped dead in my tracks by it’s sound while walking by a TV with really low end sound.
I have also had the privilege of hearing quite a few Stradivarius’ in close proximity. I also, over the last 50 years of being an audiophile have slowly migrated to an all tube system (see my system under my UserID). Attributing the fidelity of tubes to a single parameter is probably over simplifying thing. I appreciate the thought, but tubes with good electronic design can create a better gestalt of the music than solid-state, but that is because of myriad of reasons. I am sure some folks can come up with the top six reasons. But micro phonics is probably not one of them.