Agreed. Only thing I'd add is that I think a lot of the the great players of yesteryear also didn't care much about the record either. Could someone like Mizerak have broken it? I'd say yes, but at this point it's all just speculation obviously. This is not meant to take anything away from John at all.
In my little amateur world, the most disappointing part of chasing my high run is not so much getting close and missing, it's the thought of having to invest all the time and mental energy into bearing down again. I can't imagine what it's like to spend a few hours climbing into the 300s, to catch a skid, miss, or just have no shot after opening the balls, and then have to bear down a few more hours to get back up into the 300s again and then try and keep going from there. It just sounds exhausting.