One person notes your post quantity, and you characterize it as "everyone." Some people are critical of JAB and our current situation, and you call it "drivel." You characterize everything in black and white, and us against them, which doesn't speak very well for how you process 'information.'
To answer your 'basic' question, i have a not so binary answer.
If the objective, within the logical maximum period in which JAB could continue to coach—let's say 10 years as permitted by health/sanity—is to reach a Final Four, i'd put JAB's chances at even versus the field of possible replacements. But, that's just one component of what i'm looking for. If the objective is to restore us to a consistent top 20 team within 10 years, i'd put the field above JAB. We need wholesale, systemic change to do that. The zone and one impact recruit can get you into a 'lucky final four.' I don't count that as sustained excellence, which i think should be the ultimate objective.
Your last sentence says a lot. We will be very sorry if we move away from JAB "quicker." That's a weird statement to parse. So, you recognize JAB will eventually retire and need to be replaced. But, you foresee potholes or tragedy somewhere in the few years difference between "end of this year" versus "five years from now?" What's the point of that? If we're going to suffer it, you'd prefer that we prolong this mediocrity, and then hit the rough pavement? Dragging down our brand for a handful of years more before we change, thereby making the change even more difficult, with an even steeper hill to climb? For me, this is more like a certain type of examination i should have but can't seem to force myself to get. Intellectually, i know it's better to take care of things sooner rather than later. To 'know' sooner rather than later. To deal with things actively—not just allow decline and pathology to fester.