Terrorism is neither, it is a means to an end and will always exist as long as there are people who can not impact the established process any other way. If you run a government, you can create policy and send people to war if necessary. If you are not an insider and do not have the power to meet your goals, terrorism will ALWAYS be a method to make your voice heard. I think even as more people appreciate the benefits of modern society, there are still those whose voices aren’t heard.
Consider that the US is probably the most “modern society” on the planet, or at least in the top 5, and though you may not really think about it in these terms, we create a number of terrorists among our own population among those who are left behind in this society, it’s just that disenfranchisement tends to happen on a more individualistic scale here (or our society is so decentralized that people do not tend to organize as much as act on their own behalf). But consider the blue collar worker who loses his job and goes back to his former workplace with a semi-automatic rifle and blows away 13 former co-workers and the boss before killing himself…is HE not also a form of domestic terrorist?
Terrorism happens when your goal is to kill and scare people to make a point, or to get your way, when the methods made available to you by society at large do not do the job. For terrorism to end or even become a minimal part of the world at large, we would HAVE to have a situation where no one was disenfranchised…everyone would have to be able to have their needs met, and we are nowhere near achieving that goal. The only way I can see terrorism virtually disappearing from the planet would be if we were to figure out sources of renewable energy, bountiful healthy food all over the planet, an end to disease and a society where prosperity was such that everyone would need to put in minimal effort to live a long, healthy, happy life with all of their needs being met. Oh yeah, and either we’d need to settle on one God (or no God) for everyone. Maybe in another 50,000 years we’ll be there.