FWIW, ‘terrorism’ is a modern word. Historically, humans fight and kill the rival tribe. The end. For a few centuries Europeans and Americans to some degree made war a ‘gentleman’s affair’ but that’s an aberration. I agree with your assessment of long term and nasty fighting with assassinations, civilians targeted , asymmetrical, guerrilla in nature, etc.
Let the first Mosque get blown up and it will be on, car bombs, assassinations, hostage situations, drive by shootings, etc...will become the norm.