This paper explores the paradox at the core of modern terrorism. Despite years of evidence showing that terrorist campaigns rarely meet their strategic goals, groups keep using terrorism as a primary tactic. The continued use of terrorism is less about its external success and more about internal organisational benefits, such as recruiting, building solidarity, gaining media visibility, and disrupting peace efforts. Using historical examples, the article shows why terrorism often fails strategically – due to overreaction, loss of legitimacy, mismatch of capabilities, and fragmentation – yet it persists organisationally. For practitioners, this highlights the need for counterterrorism strategies that focus on organisational incentives rather than just preventing attacks. Practical steps include balanced responses to avoid overreaction, disrupting recruitment channels, managing media and communication, protecting peace talks, and strengthening societal resilience. By understanding both why terrorism fails and why it endures, practitioners can weaken the organisational drivers of extremism without unintentionally prolonging it.