I really wish that was the case. Then i'd simply plug in a piece of new equipment and it would just immediately sound better (because that's what I expected when I bought it), and I'd be done with it...
However, in my experience so far, the opposite has been true.
With the exception of one specific set of MIT cables, which I loved right off the bat, every other equipment change has resulted in my immediate reaction being: "oh sh*t, I just blew a bunch on money, and this sounds so different and really not that good....". Right off the bat, I haven't liked any new piece i've added and I always end up spending several days listening to different sources, adjust settings and speaker placement, and in some cases trying different cables. Thankfully, so far, between the adjustments I make and my ears adjusting to pick up on the features of the new sonic signature, I have ended up mostly with an improved listening experience. But it's always taken work to get there, and it's never perfect. I'm still searching for perfect...
So, while I'm not denying the existence of confirmation bias, that hasn't exactly been my experience.