Some of what you say is true, like the administrative complacency regarding facilities. But a lot of the other decisions can be traced in part to Webber's (and others') actions. Ellerbe was hired to be an assistant and was promoted because the independent report by the law firm on the scandal came down in October 1997 and left no choice but to fire Fisher immediately. With practice about to start, no coaches on the market due to the timing, Dutcher being tainted etc there was no one to hire except Ellerbe at that point as he had not been around for any of the chicanery. Then Ellerbe actually had a good year, earning a #3 seed in the tourney and winning the BTT and with probable sanctions on the way we were in no position to go get a name coach. We made the wrong but seemingly sensible at the time decision to keep him and plow through the sanctions and get to the other side. No one understood then that it would not be resolved for many years.
As far as Amaker, certainly Bill Martin screwed that up as Pitino claims that he would have gone to M. But one of the primary reasons that Amaker was hired was because he had that squeaky clean Duke image and with the case still dragging along the University wanted to appear to have changed. Moreover the scandal was still hanging over the program and limiting the pool of candidates.
Facilities - I mostly agree that this is on the administration. But don't think that the scandal also didn't turn off some of the big money people who help get facilities paid for.
You can't blame Webber directly for a lot of MIchigan basketball's problems for the decade from 97 to about 07. But a lot of the choices that other people made were influenced and altered by both the sanctions, the sense of impending doom before the sanctions and the complications that arose because of the choices of Webber, T(r)aylor, and Bullock. Their actions set in motion the chain of effects that led to a lot of shitty basketball.
Don't get me wrong, I loved going to games during the Fab 5 era and the two tourney runs were great. In the big picture, violating amateurism rules is pretty small potatoes. Forgive that and move on and I am happy to reconcile with Webber. But I do still believe that a lot of the bad basketball grew out of Webber's choices and the long lasting consequences they resulted in.