Keep in mind here that when BK was running his best times, he was doing 3 hard workouts plus a long run each week with Daniel Komen--in the winter. And the recovery runs were in the 5:00 to 6:00 range (for people running 5K at 4:10 pace). Geb seems to have a slightly different philosophy, where the recovery runs may be run slower, so perhaps the speed sessions were run faster that the Kim McDonald people. But when Bob Kennedy started to crank the volume to the level that you're talking about, first he got slower, and then the wheels started to fall off (that was before the accident).
Also consider that the non-Africans that have run 13:00 all got to a high mileage level, but it took them YEARS to get to that point.
The thing you might want to ask yourself is not whether you can get much more speed from running 140 (not likely, unless you think you're a stronger athlete than Kennedy and Baumann), but why you are running 15:15 on the same kind of training load that Kennedy and Baumann used to run 13:00? Is it just talent, or have you picked up training philosophies that don't make any sense?
Who do think you would be better off listening to, Geb or Trackhead? If Geb thinks 110 is too much for a college runner, what do you think he'd say about 140?
Cut your volume back and see if you can run your quality sessions faster--and still recover. Then, gradually over time, increase your volume to whatever you can handle, without overtraining and without compromising your speed sessions.