Of course. As pads get softer and you wear the headphones more, you get a better seal, which undoubtedly improves sound quality. My SA5000s had no bass when they were new, with time the pads got softer and now I got a perfect seal and the bass is much much more present.
Obviously measurements will tell you otherwise, but then again putting a microphone in between the pads is not a good way to measurement frequency response of headphones dependent on good seal.
yeah, I heard this before. The pads do get soft over time, and your ears get closer to the drivers as time goes on, and loses the vice-grip-ness to your head. lol. There are lots of things that can affect the sound from my experience such as the type of pads used(it can dampen the sound depending on the material), and for iems, fit and tips(type of material used, complies or silicones) makes a significant difference.
I know your brain adjust to the sound over time also. Way to really notice the difference in SQ is switch the phones quickly, but other than that even if you go to lower quality headphones, your ears adjust to the sound over time, and could sound better.