Read the Nandi resistance. Most athletes are from the Kalenjin community. These are proud people. Defeat in any endeavour could puncher that pride-thus is not accepteable.
The mindset favours success and endurance training as a boy/child makes an Olympics final a child game. Attitude, attitude, attitude baby!
We eat good food. Plenty of milk both fresh and sour (mursik) just ask Paul Tergat.
Nice excuses in the Saltin study. Of course, it must be so that we Nordics have fat legs. Gunder Hägg (15 WRs), Arne Andersson (800m & mile WRs), Paavo Nurmi (9 Olympic golds), Lasse Viren (4 Olympic golds) etc. somehow did ok even with fat legs. I just wonder if other countries made excuses back then.
It's amazing how people can do so much work just to come up with bad excuses.
I can say from the Finnish running scene that currently it is NO surprise that there aren't good runners at the top. There are only a select few doing the real training. Rolf Haikkola and Lasse Viren called this "totaalinen harjoittelu", or "total training" -- and you need about 7 years of that! They meant that you need to be willing to sacrifice almost everything for that one goal. Lasse spent several months a year somewhere just training full time. Even if he did have a job, it was secondary to his running.
Bill Rodgers has said something on the lines that no one working 40h per week can beat him. I think the same can be said that no European doing a full time job will beat a talented African focusing full time on running. From Toby Tanser's book: "even 13-year-old girls train 3 times a day".
Running together with other great runners must be useful as well. If there is no opportunity for that, then racing a lot is another option. Viren trained a lot alone, but he raced a lot. Also, his coach Haikkola was their to "whip him" on some of the tougher workouts.