1991 may not have been a success, but Chalibi played a role in that as well, making Bush's alliance with him even more mind boggling. But Bush sr. Knew better than to go into Iraq to stay. He knew he need some in power, and to create a vacuum. Bush sr rarely gets the credit he deserves.
No matter Iran's economic status, a friendly Iraq helps them. And they do have some influence (not control) in Iraq.
Nor is al Qaeda destroyed. They weren't large to begin with. They didn't send an army to hit the towers. But they got serious training in Iraq. Grew their numbers. Gained in status with our help. And did more to us then they ever could had we not invaded.
And no one suggests we can bring anyone back. But to prevent future mistakes, we must recognize the problem. Reckless spending of human lives should be harder to do.