Here are three things that you won't be able to convince me to change my mind about:
1) your weight matters a lot more than you think. Bigger runners are not always slower than leaner, lighter, smaller runners, but if a person can stay strong and healthy, they will race faster at a lighter weight than a heavier one. I am semi-fat now and running is sooo much harder.
If I did 10 killer workouts and hit all my splits, then raced a 5km, I would be slower than if I just ran base mileage, lost 12lbs, and raced the 5km. The easier way to get faster would be for me to lose 12 lbs., not by "training harder." (and no, training harder does not cause me to lose weight).
2) mileage also matters more than killer workouts. Unless you are running the 800/1500, I would prioritize getting my miles in over doing three all-out workouts each week. I used to run like 45 miles a week with three intense workouts. I was always exhausted and never had enough endurance. I should have run more mileage.
3) The best way to keep the passion and love for the sport alive is by having great friends and teammates. I use to think running "fast" and getting PRs is what was motivating me, but when those things stopped, I still loved the sport because of the people I ran/run with.