This does tend to be a theme with SG that if it no longer has a model, the rules are somehow worthless. Why else would pretty much all of Outlanders disappear? Ironically though it isn't getting the models that's the problem with pit slave gangs.
My feeling is this - most fanatics of a game (and if you've stuck with SG you're little else) are going to be able to make their own models. Models are easy to make and get (although the profit is rarely going to GW) but the rules aren't so easy to replace, especially as SG rules are typically available on the internet, the reasoning that there's no models just doesn't sit well with me. For a start it's mostly a game for Ork players, and Ork players (like myself) are converting-tastic loonies - we really don't need an excuse for that kind of behaviour.
It just seems a shame that the game should suffer because there are no obvious models. When I talk about Digganob, half of the people don't know what I'm on about. I have the book, but not that many of us do!