I've been asking the same thing for quite a while (by email and once through the forums) and nothing.
Another question is why aren't they offered through Steam with the rest of the products.
That was fun. The people at Ambrosia said that Introversion had to decide, and the people at Introversion said it was up to Ambrosia.
Personally, I find Ambrosia'a pricing totally disappointing and odd. Are people actually paying 30 dollars for games that came out 2001, 2002? In Introversions case, they have game bundle that includes Uplink, Darwinia, DEFCON and Multiwinia for 30 dollars for the PC.