Your workout days and tempo/marathon pace runs are what matter.
Of course, that is a given.
I ran the same marathon times on 85-90 as when I ran 50-55 per week. The key was run easy on the easy days and run your w/outs at the proper pace for your current level.
So you did what is considered key and still saw no improvement in going from 50-55 to 85-90 for a significant duration of training?