Right now there's some guy thinking 'haven't broken 13 in 5k whats the point' and another thinking 'haven't broken 22 in the 5k whats the point'. That is the point. Experiment with your training and find what is possible. If your performances are stagnating, try something different, because clearly you are not satisfied with the result of your current program.
Since the Lagat types who excel off quality miles in the 70ish mpw range are exceptional, try courting the LRC mantra of high-volume, low-quality miles. Gradually increase your mileage and sustain it. After months approaching the 100 mpw range, try tapering a bit and see how you feel.
From personal experience, I moved up in mileage and found that the quality mileage diet yielded best results, but I wouldn't have known that had I not tried the LRC trash mile diet