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

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.

It depends on the DAC and connection.  The "best" DAC renders the streamer irrelevant.  IF you are using USB.  If you have bought into IIS the streamer, and the cable are critical because they provide the timing.

If I had a $20,000 budget for a digital front end, $18,000 would be the DAC, $1,500 the streamer and $500 for the rest.  Choosing a DAC where isolation was an important design consideration.

My own breakdown is (approx) $25,000 DAC, $3,000 Clock, $1,400 Streamer, $1,600 cables (include Cardas Clear Reflection Interconnect DAC->Pre).  Nothing for connection as it uses WiFi (no alternative).