Its a niche product. One which is licensed from another company as far as I can tell, which makes it more expensive than other Warrlord products. On top of that being that its Weird War, rather than historical, less people are interested in it. Particularly in how that Alt History setting is implemented (I'm not a fan of all the rift tech in favour of real world prototypes which in this setting are completely ignored).
Warlord and others have had the range on Sale pretty much within a few quarters of the initial release. However as a company Warlord has picked up a load of ranges which they just forget about as well. At least the K47 range is receiving new releases - perhaps in spite of Warlord - as Clockwork Goblin seem to be enthusiastic about making more models.
Personally I'd rather the range goes back to being in its original smaller scale. There doesn't seem to be the interest with the 28mm crowd, and the style of the vehicles seems like it would fit smaller models better (with their simplistic detailing). Clockwork Goblin may make a move in future to start producing the original models again, but I think the issue's mainly the deal they have with Warlord. Which I can't comment on. However it may be a time based thing. If not then the original owners could possibly buy the rights back. ...Or Warlord will let it die like the many, many other ranges they've bought over the years.