Great coaching does go a long way toward winning. Look at the 3 QB in the playoffs that were terrible under Jeff Fisher. Look at the Rams offense versus the Jeff Fisher offense. Coaching really matters a lot.

Another example is NE where Belichek continues to excel year after year. It sure has helped that he had Brady all those years. He got fired before he got the NE job.

Great coaching gets the most out of the talent they have to work with and they coach up young players faster than poor coaches.

BUT if you don't have good talent you will not win. You may have less talent than other teams and still be successful but you have to have talent and you need to have a QB who is decent or who you can make decent. Minn created a situation where Keenum could play at a high level while the Rams failed to do that a year earlier. But based on his play Keenum would be a top 12 QB

So I would argue you better have great coaching and really good players. The teams that are good for a long time have great coaching, good talent and manage the cap effectively so that they can manage to a high level of talent on the roster. That is the winning formula.