Your opinion is that "Oracle should have assigned a whole team of developers to BTRFS" but you affirmated this: "But guess what? There is only one single developer on BTRFS. Oracle is not interested in BTRFS, now that they got the best: ZFS" which is totally FUD, you don't know how developing on btrfs is going on.
On the other hand, linux is developed by many companies, why oracle has to put all the effort on btrfs. They simply continued the project of btrfs. A lot of companies will develop and will benefit.
-There is only one single developer on BTRFS. Oracle is not interested in BTRFS, now that they got the best: ZFS
-Linux is really bad as a Large Enterprise server. It is not because of the bad filesystems, but because of limitations in the Linux kernel
Now you are beginning t to change, good! i am glad. But please don't say that you were guessing because clearly you were asserting.