not that weird wrote:
Coming out of college I was doing 60-70mpw, got my long run up to 21 miles at 6:30 pace, almost all running was well under 7 pace except easy/recovery days, and when it came to marathon day I could never hold sub-3 pace in 3 different attempts. Probably a combo of me being a headcase, poor hydration/nutrition, and some bad luck, but I can relate to OP's guy.
I've never understood the people who think marathon pace feels hard. It feels easy to me and I still can't hold it for 26 miles. No idea how you could do that running at a pace that feels anything other than very comfortable.
I think a lot depends on your physiology - what kind of runner you were. I was best at around 2 miles, but could run low 5 min per mile for a 10k, Routine shorter steady runs, I generally did at 6:00 per mile, and I couldn't have imagined running 7:00 for any kind of run. I only did two marathons, and could get through without bonking, but the only way to do that was to run about 6:20s and run even pace, so getting towards a minute a mile slower that half marathon pace.
Had a friend whom I'd probably take about 2 minutes out of on a 6 mile club training night, and who would have been 15-20 seconds slower for a mile, but he was about 10 minutes faster than me over a marathon.