"Anyone that says if you only run at say 9:00/mile easy pace can only end up running at 9:00/mile during a race is full of shit."
Yup, running lots of miles at an easy/steady pace will get you pretty darn fast, I started running in university and went from a walk on former junior hockey player running 41min 10k to a decent running in the 15/32 range running high mileage of around 100 miles per week within 2 years (also lost 35 lbs), I am certainly not the most talented and in fact was one of the slowest runners in my club in the post university track club days back in the 90s. Now running easy/steady I feel will get you 80-90 percent to your potential but you will need to do some higher quality stuff to get to your potential in the 5/10K range, I never ran a marathon outside of IM so not sure about needing quality to max marathon potential. I think the great Ed Whitlock ran close to 2 hours per day at an easy pace and his only high quality was racing quite a bit and he ran 2:50 around age 70 I believe.
Yup, running lots of miles at an easy/steady pace will get you pretty darn fast, I started running in university and went from a walk on former junior hockey player running 41min 10k to a decent running in the 15/32 range running high mileage of around 100 miles per week within 2 years (also lost 35 lbs), I am certainly not the most talented and in fact was one of the slowest runners in my club in the post university track club days back in the 90s. Now running easy/steady I feel will get you 80-90 percent to your potential but you will need to do some higher quality stuff to get to your potential in the 5/10K range, I never ran a marathon outside of IM so not sure about needing quality to max marathon potential. I think the great Ed Whitlock ran close to 2 hours per day at an easy pace and his only high quality was racing quite a bit and he ran 2:50 around age 70 I believe.