After buying NuMega technologies in 1997, Compuware seemed to feel that SoftICE was a liability, both technically and legally (as the #1 hacker tool of the time), and that may have played into why they discontinued support. SoftICE required constant updates in order to continue working against the various updates of Windows that were coming out, and there were only a couple of people who knew how to make those updates. In 2007, they closed down the NuMega office in Nashua, NH, and moved all the intellectual property to Compuware's headquarters (then in Detroit, MI). The product line that included all that stuff was sold off to MicroFocus in 2009, along with the remaining developers, none of which knew a thing about building SoftICE, let alone updating it to work with updated versions of Windows. We toyed with resurrecting the product around 2011, but could not get management to buy off on it, so it didn't happen.
The source code remains in its own stasis box (a source control database), and will likely never go anywhere from there.
Disclaimer: I work for MicroFocus, and currently maintain the formerly NuMega product "DevPartner Studio", the BoundsChecker portion in particular.