Good point.I think a different way to think of that is your tastes have evolved - which is a perfectly normal part of most hobbies. Just as our preference for music may also evolve with time, so does our preference for the sound palette that we prefer. Eg, I have a bunch of other hobbies (watches, pens, etc). In each of those cases, the stuff that I liked when i started out is not the stuff that i like now.
Trusting one's ears to decide what one likes is very different from expecting one's preferences to remain the same over time. I dont think anything can guarantee the latter (nor do i think it is even desirable - after all, there should be SOME refinement/evolution happening with experience, right?)
And trusting ears doesn't mean living with same for life. It's just at the time of purchase. Then with time & evolve u want to upgrade. Again u trust ur but this time trained . It goes on. That's evolution only.