Historically, a valid point, when one strong Muslim terrorist group is weakened, the violence continues only in a more disorganized, random and unproductive manner.
ISIS will likely survive as well, only far weaker but more dangerous from frustration. Once created Muslim terrorist groups generally never go away completely.
The only positive about Muslim fighters is that some can be a stabilizing influence when they are the legitimate military of a Muslim nation with a semi secular Muslim strongman leader. Egypt and Syria were good examples.
Otherwise, Muslims are simply murdering barbarians running wild.