Short and simle ansver: Sony Ericsson NEVER cared about having a proper phone out of this. They just ditched it when they figured out that the hardware they designed for the phone was not good enough for running Windows with the bloated SPB-Shell on it.
Because of some Liceincing-issues (most likely with Micro$oft) they can't open up the Bootloader and let users install an other OS in the phone..
Today i had 3 issues that made me furious: The keylock crashed last night, and i did not get any incoming calls to the phone. Missed 3 important customer's calls. Second was that the phone just crashed, and i did not notice it. Again missed some more calls. And the last issue 1 hour ago. A calendar alarm that i had set up to remind me to place a call did NOT ring.
So what can you expect from a company like SE when they ditched the phone practically 3 MONTHS after release (the last software-release came 3 months after release of the phone!)