Based on the rate of changes to the software for Kindles, I have to assume that their Kindle dev team is one or two people working on it in their spare time, so

Based on the rate of changes to the software for Kindles, I have to assume that their Kindle dev team is one or two people working on it in their spare time, so maybe it's lumped under the heading of "legacy format issues, we'll get to it someday". (Cynically: yes, it's probably the anti-competitive friction reason.)