Try taking a look at yesterdays news. Apple has promised a new Mac Pro with a display (from Apple), next year, and new Pro minded iMac later this year. That was a quick re-cap.
I have 5k iMac myself, configured with i5, 16 GB Ram, 512 GB SSD, R9 M390 2GB
And it is a fantastic machine, I am not the guy to talk you out of it. I use it for video editing, screencasting, games and then all the classics, mail, internet bla. bla. bla.
I think Apple does care about its desktops, they just don't know what way the market is going. And they have received a bit a battering recently with the release of the MacBook Pro. So I think they tread a little carefully. And for us, that means slow.