16 min 5k is 5:09/mi. Easy days at 7:40 are more than 2:30 slower per mile than 5k pace. That places those runs not in easy run pace but recovery run territory. Recovery runs are too slow to help boost aerobic fitness at all. Their purpose is solely for recovery.
Easy runs though can increase aerobic fitness if they are run faster. In terms of HR, recovery runs may be 120 bpm or slower, hardly more than a fast walk, not enough to increase fitness. Easy runs at 150 HR do provide enough stress to increase fitness.
Just know if you are running your easy runs at 7:40 they are not easy runs but recovery runs and you are sacrificing aerobic fitness so you can recover enough between workouts. Worked for RoJo and Mo Farah prior to moving to Salazar, and it seems to be working for you.
What remains to be seen is if you can run your easy runs at true easy run pace like Farah does under Salazar and still recover for workouts. What would make you faster, 3 workouts per week with recovery runs on easy days or two workouts per week with easy runs on easy days?
May depend where you are in your training cycle. The closer you are to your goal race the more important the workouts become so 3 per week may be better. During off season, aerobic fitness should be the goal so 2 workouts per week may suffice.