"even if, as was the case with this decision, Red Hat was never a big contributor or fan of btrfs."
This is not accurate. SUSE's graph actually shows that Red Hat *was* a big contributor to btrfs from 2009 to 2012; Red Hat is the darker red that comes second from the top in the bars. It looks like in 2011 and 2012 RH was one of the largest contributors.
As I've written elsewhere, the story of RH and btrfs is basically that we were indeed quite enthusiastic about it initially (as those numbers show), then we got less enthusiastic about it and tailed off contributions and future plans for it correspondingly.