Tom Izzo missed the tournament in both of his first 2 years at Michigan State. He was an abysmal 16-16 overall in his first year, with a slight improvement to 17-12 in his second. HE HASN'T MISSED THE NCAA TOURNAMENT SINCE (that's 15 seasons).
Billy Donovan missed the tournament in both of his first 2 years at Florida. He was an abysmal 13-17 overall in his first year, with a slight improvement to 14-15 in his second. He has missed the tournament only twice since then (that's 14 seasons).
Tom Crean is perhaps the best example. He 'inherited a mess.' He had 8 total conference wins in his first 3 years, with 20 or more losses in each of those years as well. Didn't even make the NIT once! Now he's got Indiana back at the top. Further, I don't remember anyone calling for his head after the third terrible year. Their fans, unlike you, understood that, in fact, there IS something to be said for 'inheriting a mess' and 'needing time.' They, unlike you, understood the concept of 'rebuilding.'
I could go on; there are more examples like these. John Beilein missed in 2 of his first 3 years at Michigan, Thad Matta missed in 2 of his first 4 at OSU. You get it. I'll stop here, though there are probably more.
CCM may or may not be the answer, but the point I'm making to you is that there is no way to be sure as of yet. It's simply not as cut and dry as you attempt to make it. Period.