Henra
That thinking has been repeated here again aind again but after a biref reality check it doesn't hold water.
which terrorists got which publicity that would support their cause?
The world has changed. Terrorists used to want specific goals. That meant they had to identify themselves (or their demands identified them).
Now it is a broader goal. The goal is to create terror.
No one claimed responsibility for 9/11, nor for various incidents since. Terrorist groups have been held responsible, but they haven't claimed responsibility themselves.