So you are claiming that NeoCons have existed for 50 years with the sole purpose of invading Iran, and somehow have failed to even get close?
NeoCons, also known as Neo-Reaganites, came about after Reagan. They believed that even after the Cold War, Reagan would have wanted to see an America that aggressively engages with the world. They were Republicans, because Democrats would not care what Reagan would have wanted. Throughout the 1990's NeoCon groups like the Project for the New American Century, and The Vulcans(Rice's led Bush foreign policy advisors) focussed more on what being "aggressively engaged" would actually mean.
First as a side note, they were an offshoot of Kissinger's political realism, which assumed that only nation states were actors on the world stage. It was impossible for a non-nation state to do anything interesting internationally. If there is one doing so, it is a front for a nation state. Therefore, the NeoCons did not believe Al Qaeda could or would attack America in a meaningful way. No amount of proof would convince them that 9/11 happened like it did happen. This was not part of their plan, or even a possibility in their world.
So their plan was to invade 5 to 10 countries over 10 to 20 years at the beginning of the 21st century. Each country would be in a different region, and would be quickly turned into a "seedling democracy" that would not just be a democracy, but would turn its neighbors into democracies. The whole world would be transformed in 20 years or less, and then we would have the American century that they speak of.
They had already picked Iraq to invade, so had no reason to invade Iran... at first, but then everything went wrong. Well, first it went wrong with having to invade Afghanistan before Iraq, but then it went wrong in Iraq. It turns out that you cannot turn Iraq into a showcase democracy in one or two years, that the Iraqis would continue to fight against an occupation of Iraq. The NeoCons blamed Iran for their failure in Iraq, and started to talk about invading Iran too.
Meanwhile, American politics began turning on the NeoCons. Their entire ideology had failed, and everyone but them saw that. The Project for the New American Century collapsed even while their members were ensconced in government. It made the directionless Bush Administration even more directionless.