The fact that Blanton Collier ranks number four on that list, above coaches like George Halas and Paul Brown, is all the evidence necessary to show how meaningless that ranking is.
May as well look at the career playoff passing yardage leader board and surmise that Cam Newton is better than either Bart Starr or Johnny Unitas.
What's wrong with Blanton Collier? He was HC for 8 seasons and got to the Championship Game 4 times (50% of time). He won once with a brilliant game plan to beat the vaunted Balt Colts. And while he had Jim Brown for 3 of his seasons, he continued to do well after Jim Brown retired.
What's your issue with Blanton Collier? His win %age is reflective of his success.
The only thing you can say is that his 112 game career as HC is too short. And I used a 100 game cutoff. 100 seemed ok to me. Vince Lombardi only coached 136 games, and John Madden 145 games. I suppose if I used a 125 game cuttoff, Blanton would drop off this list. But a 100 game cutoff is as arbitrary as 125 game. Blanton had a decent career, won a Championship, got to 4 Championships.
And yes George Halas won 6 Championships over his 450 game HC career, and Paul Brown won 7 Championships. Noone is saying Blanton is better than them for post-season or for winning Championships. For that I suppose you should calculate Championships per season coached, which for Blanton would be 12.5%. On that Shula with his 2 Championships over 33 seasons would look pretty crap.
Anyway, these stats were about winning %age. Winning %age gets you to the postseason. After that a whole bunch of other statistics can take over. I agree that post-season stats are more important, but I don't think that makes regular season stats irrelevant. After all you have to perform to get to the post-season!