I don't think it's a liability problem at all. They just recognise that their product is not going to be one of the big players in PEX and they are never going to reach the profits that they want to achieve.
The brand while good quality, I consider it to be one of the better systems but, has never been the most popular. I believe with the low market share they had they were just unable to compete and didn't think they would get the federal bailout that GM, Ford, or, Chrysler might be getting. Without a doubt Wirsbo/Uphonor is the Big Kahuna and Viega is probably in second place, or, at least close to it in the also rans.
I think it was just a case of them deciding to stop...
You will note in the release that they are also discontinuing production of PVC. If your following the liabiliy logic then we all better start worrying about all the PVC we have installed...

Dark clouds are looming on the horizon!
Face it the economy today just plain sucks!
There are a lot of businesses that are going to make tough decisions that their survival will depend on.
The better product doesn't always win in the marketplace. Anybody remember the VHS wars? VHS vs. Betamax? In this case the superior product lost! Betamax had better picture quality, and better sound quality yet the only users ended up being the professionals. Those News clips you watch every night were mostly shot on betamax but the video rental and sales went VHS.
Now we see the same thing happening with DVD...
Go figure!