As I learn a new piece of music that is at or just slightly above my skill level, I'll find myself basically just struggling through it the very first time I pick it up. I'll be unfamiliar with the chords, dynamics, etc. My major focus is to hit the correct notes, and attempt to hit the correct timing. As I become more familiar with the piece, I start to smooth it out, add in my own interpretation and so forth, so that eventually it sounds the way I want.
However, when I attempt a new piece that is just below my skill level, it goes a lot more smoothly, and I can get the piece to sound approximately how I want, maybe a bit slower than written, or perhaps with fewer dynamics, but it tends to go much faster and it starts to sound like music as soon as I get going.
My question is this: as I've progressed through learning the piano, the pieces that are at my level or just slightly above have never gotten any easier. I feel the exact same way I did when I first started playing years ago. The pieces themselves have become more challenging, but the mental effort I need to put into a new piece has never really relented. Is this similar for an accomplished, perhaps professional pianist as well? Or does there come a point where a master pianist is just so familiar with the instrument that playing the notes is no longer the problem, but playing the music and interpreting it is?