the biggest problem with nfl teams not "getting over the hump" IS the coaching or rather how poor overall coaching IS in the NFL when you compare success.
you have "Darth Bill" as the #1 coach in the league then you have...who in the AFC/NFC?
most head coaches in the league are either mediocre or "new" (ie been with team under 4 years) thus have no sustained track record of success-since they are new.
tier 1
Belichick - 19?yrs as the head coach of the patriots, since 2001: superbowl 8 times, conference championship 12 times, & made the playoffs 15 times.
tier 2
Tomlin- great coach in the regular season, surrounded by talented players, yet...loses in the playoffs pretty most of the time in rounds 2 or 3. - 8 playoff appearances since 2007 (tomlin took over i think in 07) 2 superbowls 3 conf championships, 8 playoff- a record of success, -except vs BB.
Reid - great coach in the regular season, surrounded by talented players yet loses in the playoffs in rounds 1 or 2- pretty much every year.
tier 3
everyone else
nfc
tier 1
none
tier 2
carroll
mccarthy
peyton
tier 3
everyone else
now this is not to say that the new coaches won't move up, but at this time, they do not have the record of past performance to say...this coach is really good, POTENTIALLY there are -imo- 4 or 5 new coaches that have a shot, they just have to get results to put them in the same category as whom i am calling the tier 2 coaches- sustained success in the regular season over the course of several years.