I mean, let's assume that Islam is the main source of the majority of problems in the Middle East. But how would something like that even be addressed? You can't force a mass deconversion of people or divorce a religion from many cultures abruptly; you'll only end up antagonizing people and push them further away from what you wanted. (Suggestions of committing genocide are even more laughable.) And combating fundamentalism without addressing the foundation of inequality, poverty, and political instability upon which it is built will only address a symptom of the issue. Any other ideology or religion could be propped up to serve the same purpose. Any beliefway could be twisted to serve an ideal. There are several underlying factors that are conducive to the problems we would like to see solved, but the approach some are taking is unhelpful at best. And usually, the Muslims that are not affected by such factors around the world are moderates or very strongly against extremism, fundamentalism, so I'm not convinced that it's a Muslim issue (or that characterizing it as such makes it easier to tackle). Otherwise, we would have never seen the historical, progressive changes in the Christian world if the problem was so simplifiable.
I don't know if Islam is the main source of problems in the ME. I'm pretty sure it's a major source. So, assuming that's correct, how can it be addressed? Frankly, I don't know. It'll be up to smarter and more dedicated people than me to come up with solutions. But it's clear to me that it'll be much easier to come to a solution if more people can accept that Islam can be a contributing factor to people believing and doing bad things.
As for your other points, I'll try to briefly address some of them in the order you brought them up:
* In fact, many Muslim-majority countries have successfully and abruptly reduced the influence of Islam and made their populations more liberal as a result. All in the 20th century, too. Turkey, Indonesia, Albania, and the ex-Soviet Central Asian countries are the obvious examples. The governments of these countries all suppressed Islam, forcibly and sometimes brutally. Note that I'm not suggesting this as a solution; I'm pointing it out because it's clear that Islamism can be effectively reduced and Muslims can be made less devout. Is there a liberal way to do this? I'm convinced there is, although I don't yet know what it is.
* Inequality, poverty, and political instability did not seem to stop the success of the de-Islamisation campaigns I mentioned above. I've actually seen no evidence (or conflicting evidence) that inequality/poverty and radical Islamism are even correlated. Political instability seems to be, but Islam may lead to or maintain political instability in the first place.
* I'm not convinced that any ideology could be propped up to serve the same purposes in the same ways as Islam. I mean, that's essentially saying that all ideologies are devoid of content, and they're mere cosmetic appearances covering a core that can be twisted to any purpose equally effectively. Boiled down further, it's saying that people's ideology or beliefs have absolutely no effect on their actions. It's an absurd idea.
