Did you ever drive a car just once in your life? That is 530,600 total miles. I know that you didn't log them all yourself but, damn!
Well, let's see. I do own and operate a pickup truck. It gets about 10,000 a year. Those are all my miles on those bikes as I was only counting the ones that I put on them if they were used........and I didn't include all the miles I put on the little bikes back in the 60's and 70's. I'd guess there to be another 50 to 60K there.
All one has to do is use his/her bike for transportation and dedicate travel to riding and then do it for 35 years and voila, next thing you know, you're approaching that million mile mark. I know professional truck drivers that have millions of miles under their belts.
The downside is that every time I go to trade or sell one of my bikes, potenetial buyers are put off by the miles regardless of the normally good condition it's in. One does become proficient at maintenance when riding frequently. For example, I figure the ST1100 I have with 113,000+ miles will be a give away when its time comes, so at theis pont, it's easier just to keep it. It has and continues to serve me well.