Elite runners don't log super slow runs ever. Maybe they did in the past, but just look at the logs of any top distance runner in the world. You will never see an easy run slower than 6:30/mile. That slow of a run is completely a waste.
If you are a 16:37 5k runner and you don't recover enough after a full nights sleep to run 7:30/mile for your pace on a run then you are over-training or aren't recovering nearly as much as you should.
Here are some examples of elite guys easy runs that I have read about:
Chris Solinsky 5:45/mile on easy runs
Hicham El Guerrouj - 5:10/mile on easy runs
Keninisa Bekele - 5:30/mile on easy runs
Galen Rupp, Cam Levins, and Mo Farah - 5:50/mile on easy runs
trials of miles and miles of trials will always beat hard/easy