As to the why: I think it is two things.
1. He knows it can be an effective defense. It is far more effective than most M2M defenses when played properly with the right personnel. We know that, we've seen it.
2. College teams have very limited practice time so committing to one thing increases the efficiency of practice time. There is also no doubt that this is true and is an absolutely reasonable approach to college basketball.
Problems:
1. This is clearly the very worst zone defense I have ever seen. Last night was laughable to an extreme degree.
2. That is likely an outcome of what was said above: there has been far less practice time than a normal season and our players, specifically the top of the zone are particularly ill suited to playing it well.
3. The fundamental problem with item two is that Buddy and JG3 are partly ill suited for the zone due to a lack of length (Joe) and a lack of athleticism (both). Both of those problems would be even more glaring in a M2M defense.
Kadary has the length and athleticism to be murderous at the top of the zone, but he doesn't have nearly the experience with it (he also left shooters wide open last night) and that problem isn't likely to be solved overnight.
All that said: the typical arguments against playing M2M are outlined above and they are reasonable, even if you don't like it. This year, since the zone is so bad, it might be reasonable to try M2M because how could it be worse. I suspect what JB would say is that using last night's game as a reason to switch is illogical because, while we might do better against a team like UVA, we might lose to other teams as a result of playing a M2M that we didn't get much practice time to refine, or matchups would be different in such a way that the zone would fare better.
I would agree partially with that. Let's face it, we can't use UVA as a litmus test to determine if our approaches are valid at this time. We just can't. They have what, 8 losses in ACC play since 2017? And hell I think two of them are to us. So NOBODY does well against them (we maybe one of the best against them in all honesty) and it is a sort fools errand to try to mold our entire approach to that particular team when we are having trouble beating teams of the ilk of Pittsburgh.
Thanks for your thoughtful response, I appreciate it, and certainly respect your perspective. That stated, I'm not persuaded enough to concur fully with your point of view.
As to your why: I agree with #1. In regards to #2, I would say, yet 99% of all schools/coaches out there under the circumstances you mention, commit fully to m2m as their 'primary' defense. It's not as if JB is the modern day Elon Musk and has literally reinvented the wheel here, and no one out there is trending JB's way/investing in his yesteryear technology/train of thought.
As to problems: #1 fully agree with. As to #2, JB's apparent stubbornness & unwillingness to adapt, has pigeonholed him by not utilizing his assembled personnel where they may be best suited. It appears he has options, some have mentioned Kadary and Griffin at the top of the zone. Same applies for #3 here, and I don't think many would say that neither of those two are not athletic enough in m2m.
In regards to
"the typical arguments against playing m2m as outlined above" sentiment, my reply would be how does a program the stature of Syracuse even faced with such a dilemma? And, these "typical arguments" are nothing new to the program. Syracuse, according to many here, and I think the many many more that are not fan board diehards, but about in the greater community would probably opine that SU is in a group of schools right after the blue bloods. As I mentioned earlier, SU is the 6th winningest program in NCAA history, not to mention being in one of most premier P5 hoops conferences in the ACC, with a chitton of resources available. Therefore, gathering/assembling an athletic enough team to compete at this level should seldom to never be an issue, let alone actually being physically unable to play m2m. If I'm being fully transparent, the thought of such is laughable, if not completely unacceptable.
I wasn't suggesting that UVA be the litmus test. However, one can argue why not. Unless of course, as Alsacs has pointed out in several of his posts, the SU fan base is totally good with accepting our new normal of being a middling/mediocre program vs. being at the top of our league chasing conference titles as once accustomed. Perhaps, I am guilty of living in the past, since we are now on our 7th straight season of double digit losses and not being ranked in the Top 25 come January since 2014.