It was shut down for a reason. NCsoft likely didn't view it as having any additional growth potential, so while it was marginally profitable and sustainable for them they wanted to clear up financial resources and market space for the upcoming releases of GW2 and WildStar. It paid off with GW2, not so much with WildStar.
It's a sound business decision. It's not going to earn them many fans, especially amongst CoH players, but from a broader business perspective it makes sense.