Even though they denied it, I'm willing to bet that SuSE (and others) made the move after realizing the Reiser community was about to be abruptly beheaded.
Not just beheaded (a particularly gruesome term in light of this topic), but to have a very negative association. Remember that SuSe is open-source but supported by the very corporate Novel. I don't know that I'd want that association with my company, and the suits running Novel are probably less inclined.
The arrest was likely the instigator, but at that point it had long been clear that Reiser4 wasn't going to be accepted in the kernel mainline, and Reiser3 had gone off into an 'unsupported' limbo. The switch would have happened sooner or later.
