a) it is a lens with pretty limited application (limited to F8)
b) the IQ of the lens was never considered an unalloyed success (great CA characteristics, very dodgy bokeh)
But on the flip side
c) its an autofocus 500mm lens that can be handheld and costs only about $US700.
A fuller review is given over here at Alphamountworld.
So already we have a lens of mixed blessings but I would also remember that Sony has a new mount to worry about and has been quietly shuffling old Minolta glass out of the inventory. Combine all this, and if its true that the only AF mirror lens is getting retired, I am saddened but not shocked.
If you want one, get in quick. I'm not sponsored by BHPhoto in any way (though I would love to be - shameless plug) and I get nothing from this but they have always been great to me so here's a link.