But the real reason he quit now, in the middle of the season, is a simple one: Nepotism. Bob Knight (or someone in his circle) announced at least a few years ago that his son Pat, would take over once the Classic Bully quit. The story then was that Pat's recruiting was so bad that his dad would have to renege on scholarship offers.
But by quitting so abruptly in the middle of the season, he can command the continuity of his son in this major conference program. Even if he stinks.
If he quit effective at the end of the season, the athlectic director, et.al. could do a search for a real coach. Now, Little Knight will get the half season, then demand his own chance, not just 10-odd games.
The same thing is done all over American coaching, business, and politics. It still stinks, and hopefully Texas Tech will have the guts to make Pat the Passer earn his job.