What are the implications for a company's customers if its main patent has been assigned to a competitor after litigation?

I agree with the previous poster: in all likelihood, there is a license back to sell products or the product has changed after litigation somehow.

But I don't agree that the company would be the only one liable. End users can be liable for copyright infringement. The customer might look to the company for indemnification, but infringing use of a patented product is still infringement.