From the article:

ESA is not prepared to pay NASA's share when NASA has left the space station," [ESA Chief] Dordain told reporters Tuesday night on the sidelines of the space summit.

"If NASA is staying, we are ready to follow," he added. "If NASA is quitting, I shall not propose to ESA to pay part of the cost that NASA is covering today."

Fair enough that NASA isn't pushing to deorbit ISS no matter what, but, it seems like they are saying they won't put a dime into it, and ESA is saying they won't pick up NASA's share. So what's the alternative?

Also worth asking: are there any technical factors that *require* NASA involvement, such as spare parts only they currently make, ground control and support facilities, TDRS coverage, etc. Sure ESA/Russia could duplicate those but that adds even more to the costs they'd have to shoulder.