> AFAIK, Honeycomb was primarily for tablets due to the (then current) UI scaling terribly and primarily being for portrait orientation. This was the era of 320x240 screens, after all, so there was bound to be some issues when scaling that up to tablet resolutions.
No, not at all. Android's UI has scaled exceptionally well since long before then, and nobody on Android was using 320x240 screens at that time. Android had already long since done the high DPI jump from 320x480 (HTC G1) to 480x800 (Nexus One).
You need a UI that takes advantage of the extra screen real-estate, yes, but there was nothing about Android's core UI toolkit that failed to handle that in any way.
> Since most of the improvements ended up being useful for the upcoming "phablets" as much as tablets, Google just merged those features into Jelly Bean and gave up on a separate tablet UI.
Google never actually forked Android for tablets, so there was nothing to "merge." They just focused on the tablet UIs & devices such that the phone ones had bugs. You can boot up Honeycomb on a phone-sized device and poke about. Everything's basically there, it's just super buggy.