Lol, here's the secret.
That isn't a real piano, it's a virtual instrument (that's over 50GB in size) playing back MIDI data. I record myself playing, yes, but I'm just recording MIDI data into Logic, which means I can edit each note individually, how hard it's pressed, how long, which note, etc ect. Honestly, I don't do
that much editing. It's mostly timing. I tend to relax and take my time when I play these in, and then I edit out all the dead space and give the improv a better sense of timing and movement. Of course, in the rare instance of a missed note, I can fix that as well, since it's just MIDI.
Don't tell anyone!