OP's argument is mostly this
IBM hosted that meeting, but ultimately, never did contribute any developers to the btrfs effort. That's because IBM had a fairly cold, hard examination of what their enterprise customers really wanted, and would be willing to pay $$$, and the decision was made at a corporate level (higher up than the Linux Technology Center, although I participated in the company-wide investigation) that none of OS's that IBM supported (AIX, zOS, Linux, etc.) needed ZFS-like features,because IBM's customers didn't need them.
So it's about money and they don't care about innovation or anything like it. Just like Microsoft.
It's such a shame that Red Hat was sold to these guys, Red Hat did so much good for the linux community.
But this is all in the past now, we won't see any improvements coming from them that don't directly relate to company profits.