Also, Daesh is arguably in worse shape than AQ in terms of losing senior leaders. Guess all that sectarian mayhem in Iraq and Syria, unilaterally declaring a "caliphate" over a massive region of said countries, disobeying bin Laden's and later Zawahiri's orders, and painting a global target on their backs to an unprecedented degree via the taped beheadings of Western hostages, horrific mass attacks in European cities, and generally "not playing nice" with anyone, including fellow jihadists, is poor strategy long-term!
There's an amusing class division at play here too. Consider bin Laden's and Zawahiri's backgrounds vs. that of the godfather of ISIS, Abu Musab al-Zarqawi: two scions of incredibly wealthy and educated families vs. a literal street thug who found religion in Jordanian prison.
In any event, the vast majority of insurgencies fail, because at the end of the day, states can be even more violent.
