Say you run 60 mpw and do a tempo workout each week, long run, etc.
Then you do 80 mpw and do the same exact workouts (i.e. the distance/intensity does not change), but your easy mileage increases 20 mpw.
Then you take someone doing 100 mpw and they do the same exact workouts.
How would all this translate into marathon times? If you're a 3:00 marathoner on 60mpw what would you expect the 80 and 100 mpw folks to be at? Obviously this isn't a scientific exercise but I'm curious as to your thoughts of the value of the extra 20-40 mpw of easy running.