I don't think that they're making any sort of direct choice to stop doing those things. I just think that their current desktop manager choices have been bad. I tried installing the latest Ubuntu on my main desktop PC this past weekend and it was a failure. I did get all my drivers working, but they didn't work out of the box anymore. Even once I had them all working, Unity seemed very unstable and in general the experience was very disappointing. It appeared to me that they were positioning themselves so that they could start throwing money making ad software and garbage onto my desktop. Now with the recent blog announcements that they might be enabling direct-from-desktop 1 click purchases and stuff, I doubt I'll ever consider installing it as a desktop, again. At least without xwindows, all of the original reasons for why Ubuntu was awesome still shine.
Also, drivers are just as bad as they were back in 8.04. I still can't watch a fullscreen YouTube video without terrible stuttering, screen tearing or audio lagging. And before you say so, no, it's not my computer hardware that's causing these problems.
If you are a long-time Linux user then you should not have a problem using apt-get or synaptic, or installing xubuntu-desktop or whatever you want. You should also be familiar with the concept that some hardware does not come with good Linux drivers. Ho hum.
Any popular linux distro lets you choose your desktop and almost everything else, the main reason to choose one distro over another is your faith in their package curation