Using one of the top 3 or 4 coaches in the country as an example is not a valid example. I mean, you can't say that Bill Self could do it, then say if someone can't, they just aren't a good coach. That is ridiculous.
I'm just trying to make the point that good coaches almost always are able to get to teams that have below average talent to play at an average to above average level. I may have used some hyperbole in the process. There are exceptions to that, but even then, it doesn't take them long to get enough talent in the program to get them to that level. Scott Drew took over the biggest mess imaginable and had them in the tournament within five years, and that's a program with almost no history of success. Good coaches eventually overcome bad situations almost 100% of the time.
Good coaches don't often have below average talent and when they do they struggle. Drew is a great example. They were absolute crap for four years before he got good players.
2003–04 Baylor 8–21 3–13 11th
2004–05 Baylor 9–19 1–15 12th
2005–06 Baylor 4–13 4–12 12th
2006–07 Baylor 15–16 4–12 11th
Name an actual real-world example of a good coach having
below average talent that you can think of that didn't result in a poor season (missed the postseason altogether seems to be your barometer).