I’d probably rank quite well amongst the general population. But I’m talking about fitness enthusiasts here, specifically the subgroup of long distance runners. Within that group I’d probably be “not bad”…
You run 4-5 marathons a year. That is more than many professional runners, who usually limit themselves to 4 a year max, because of the sheer amount of stress a marathon puts your body through. Add in the ultras, and you are running more than pretty much anyone being paid to do so.
You do not rank "quite well". You rank in the 0.1%, and even amongst fitness enthusiasts, you also rank easily amongst the top 10%. Not necessarily in terms of speed, but in raw distance done.
That’s not a very good way of looking at things. Professional marathon runners have a completely different set of priorities to me, and perform at a massively different level. Eliud Kipchoge has only run 2 marathons so far this year, I have run 3. That doesn’t make me 1.5x fitter than Kipchoge, or say anything at all really about the relative level of fitness between him and I.
I run a lot because I love to run. But I don’t set a competitive pace in any of the events I attend. I would claim to have rather strong knees, but that doesn’t translate into pace or fitness, just into mileage and a certain level of resistance to knee injuries.
You do not rank "quite well". You rank in the 0.1%, and even amongst fitness enthusiasts, you also rank easily amongst the top 10%. Not necessarily in terms of speed, but in raw distance done.