Like others, I cannot explain why you didn’t perceive differences. I already know you can explain why i do - you believe it confirmation bias. I have explored that in depth as I’m quite aware of that tendency in my own line of work so I try pretty hard to not fall into that trap and so I don’t think that is what’s happening. For instance, I’ve listened to a lot of quite pricey gear (amps, DACs, cables) in home which I’ve returned because even if I could perceive a difference - it wasn’t enough to merit opening my wallet. I’ve spent only when I felt it merited it.
I took my streamer (some would say high end - others mid range at >$5k) to my local dealer (who’s now looking to consider the brand). I first auditioned his Simaudio 680 DAC using their built in Mind2 module. Then we played the same track sourced from my streamer (via USB input on the DAC). He was surprised at how much better it was than the onboard module. I was actually hoping to sell my unit and reduce boxes. My bias (strong) was to favor the 680 as DAC w/ streamer. I came away disappointed and kept my streamer and went another direction w/ the DAC.
Yes, bits are bits. The data arrives fully intact. I will not dispute that. But the data is delivered in an analogue wave form with a slope to the rise and fall which affect when those 1 and 0s are registered (jitter). And, noise (not hiss) is carried along for the ride - affecting the same.
Are differences night and day? Some would say yes. I would say no. But, for those of us pursuing higher performance, they were perceptible - and valuable. I perceive more spatial information (openness and depth as opposed to a flat soundstage). Tonally they are essentially the same. But, depth is significantly better w/ the better streamers.
By the way, I had also auditioned the Bluesound Node 2i and Lumin mini streamers going into the Marantz reference player/DAC. I heard very little difference between those two unit against each other, and only minor differences between them and the Aurender N100H I owned at the time. Things have progressed since then and I’m comfortable w/ where I’ve spent - and not. I suspect others feel the same.
Perhaps you should ask one of the better companies out there to explain why there are differences. You might come away confident in your current position. Or, you might begin to wonder if you’re missing something. Let us know what you find.