He was running low 2:40s for years but not doing a lot of mileage or hard workouts because of work and family, and then he focused and brought the old Stanford talent to what was still a light training regimen of eventually 65-70 mpw in his 40s. Very impressive because usually you don't see these kinds of breakthroughs at that age when you've been running marathons already for fifteen years, and this goes about 5-7 minutes beyond the shoes. If he could stand 100 mpw, he might go low to mid 2:20s still.
Well the easiest way to be in the best shape of your lifes in your mid 40s is to be in bad shape in your 20s and 30s:). The impessive part is the ability to up training late in life. For most of us it isn't just work and family that does us in. It is also our ability to recover. People like to focus on the energy return of the vaporflys but I wonder how much the new foams also make it easier to get in the mileage by stressing the legs just a little bit less.