The terrorists seem well-ensconced in their twin nerve centers for Iraq and Syria, Mosul and Raqqa, respectively, and do not appear threatened in Fallujah, only miles from Baghdad. This despite the allied air campaign designed, in President Obamas words, to degrade and ultimately destroy the group.
Airstrikes alone will not defeat the ISIS. If the NATO is serious about destroying the ISIS, then it should bring in the infantry and the battle tanks. For every 10 terrorists killed in the US-led airstrikes against the ISIS, 50 more joins them after crossing the Turkish-Syrian border. ISIS has also stepped up the recruitment of local Sunni Arabs.
I think this will only stop when everything comes under ISIS in Iraq. Only then it will be affordable for US or NATO to be at War with ISIS. Even Russia will be eying the opportunity to let its army go into the war.