You're assuming a number of seemingly questionable propositions about "potential terrorists". Do they really care more about personal outcomes than mission outcomes? (I might not mind that I'm caught, if my colleagues succeed before they are caught.) Do they really care so much about "high stakes"? (If I'm comfortable with martyrdom I may be comfortable with a number of other outcomes.) Are they actually so willing to substitute "alternative forms of terrorism" for the sorts of acts that have been successful before? Do they care about returns on "investments"? (Those who fund operations may be civilians in some sense, and not the same people who take decisions regarding the use of those funds or of other resources.)
Besides, the point about alternatives is problematic in other ways. If vast public resources are expended moving problems from one location to another location, were those resources well spent?
Besides, the point about alternatives is problematic in other ways. If vast public resources are expended moving problems from one location to another location, were those resources well spent?