Perhaps over time you're tuning in more and more to your particular reeds so don't need to be quite so up close and personal with it.
Also maybe the more you play the more you'll unconsciously know where your fingers are going so don't require as much feedback from listening to what you're playing....... but it's only a guess!
Looking at my friend who was sat beside me on monday night, he took up melodeon in about '76, so by now he just knows where he's going and what his fingers are playing. He's also annoyingly good!
I keep reminding myself something I think Theo said after I'd been playing for a month or two - it takes time.
Never a truer word said.........
Q