Can the West afford to nation-build the entire Middle East?

Emma Sky, General Odierno's Chief Political Advisor in Iraq, writes informatively in the Foreign Affairs March/April issue. She ends her article with the following paragraph:

"Iraq still has a long way to go before it becomes a stable, sovereign and self-reliant country. Continued engagement by the United States can help bring Iraq closer to the American vision of a nation that is at peace with itself, a participant in the global market of goods and ideas, and an ally against violent extremists. Under the terms of the Strategic Framework Agreement, the United States should continue to encourage reconciliation, help build professional civil service and non-sectarian institutions, promote the establishment of checks and balances between the country's parliament and its executive branch, and support the reintegration of displaced persons and refugees. US assistance is also needed to bolster Iraq's civilian control over its security forces, invest in the country's police units, and remove the Iraqi army from the business of policing. Should Washington fail to provide such support, there is a risk that the Iraqi government may become increasingly authoritarian rather than democratic--undermining the United States' enormous investment in blood and treasure."

According to Joseph Stiglitz the cost of the Iraq mission is about $3tn, ie the current entire Chinese foreign exchange reserve would not pay for this. Seven years into this nation building and efforts are seemingly needed to run the place. Is there really an end in sight for support in Iraq?
We have just engaged Libya one of many states currently in turmoil. This time so far without people on the ground. Perhaps this is going to work better but the rebels in Libya, and perhaps many others in the Arab world, seem to demand help.
My feeling is that the countries in question should, if they really like to emulate the West, do so spontaneously. The West should only use soft power. However, if it is decided that there is a security argument for the West to engage in nation-building, this is going to have to be an argument on the order of preventing World War III to be sustainable.
It must be reasonable to assume that the countries in North Africa and the Middle East can develop a new way to govern themselves post-Arab Spring. According to Emma Sky above this is unfortunately going to gravitate towards an authoritarian model.