No way Coe could have run 3:38. He was considered himself an 800m runner, and thats how he trained, and thats why his most impressive mark is his 800 PR. Coe hit the exact mile time he should have hit based on his training. When Coe was about 18, his dad predicted what his liftime PRs would be and when he would hit them. Every single prediction was EXACTLY right, as he ran 1:41, 3:47, 3:29, just as he predicted. The only difference in Peters predictions were that Sebastian ran his 3:29 later than when Peter thought.
You can do the hard/long method if you want to but what is the point when the hard/fast method takes less time and produces the same results? The hard/fast methods of Coe also produce much more longevity as far as competetive running goes. Jim Spivey, who was coached by Dr. David Martin (who worked with Peter Coe) had one of the longest and most consistent careers in american history. He was able to run 13:17 in 1983, and ran 13:15 11 years later in 1994. No Lydiard mega mile runner could ever hope to have a career that long, they would get burned out, injured, or whateveer.