Why in some instances does changing streamers makes a bigger difference?

I rewatched the video more carefully (initially I'd just watched bits and then fast forwarded.)  I think it is a first class piece.

I have said in other threads that the engineering of the DAC is critical for consistency.  Esoteric is, first and foremost an engineering company and achieves that isolation of output from input glitches - and then gets great SQ.  That said, it is altogether possible that there are DACs that make beautiful music only when fed with clean input.  If such a DAC meets your SQ needs then your streamer may well be important - the DAC designer put their efforts into the sound, perhaps to meet a price point.

I think the main point is that connected equipment interacts electrically and that these interactions cause DAC clock timing perturbation, causes faults in the D/A conversion accuracy. This makes sense to me... we can send data across the planet unchanged but when we try to convert it to analog it becomes vulnerable to corruption. 
 

@retiredaudioguy 

In the stuff below the capitalized DAC refers to the whole component and dac revers to the innermost guts - the chip that turns the digital data into an analog voltage/current

This is a convention I have used in these threads, and I hope it gains widespread support!

In addition to many technical differences that may occur among streamers alone, DAC used and protocol used to connect from streamer to DAC is key.   For example, using an asynchronous USB connection from streamer to DAC puts the DAC in charge of the clock and reduces role of streamer in resulting sound quality.

Does better equipment (DAC especially,  Preamp, Amps) Negate the need for a better Streamer or make it more discernible?  Hmmmm.  I have found the latter to be true in my systems.