But the point of this is that unpopular occupation forces trying to impose their will never really works in anything even remotely like the long-run. The only times it can work is when a genuinely popular (and not artificially propped up) leader is able to find common ground with the "enemy". For instance one of the best decisions we made after WW2 was with the leader of Japan, Emperor Hirohito. We actively avoided not only attacking him, but did not try him for war crimes, and let him retain control of the country after the war. He chose to lead Japan in a different direction following their defeat, and everybody came out all the better for it. It's very likely that had we executed him, or installed a puppet, that Japan's relation with the west would be radically different today.
The Emperor of Japan was part of a very old, very well established monarchy; his legitimacy in the office of Monarch far outweighed that of Saddam's in the office of Tyrant.
In general, the more likely reason is that most people tend to be resolutely incurious about foreign politics. There are, IIRC, 150-ish ongoing armed conflicts in the world right now (and this count is far lower than it was 50 years ago!). I suspect that even reasonably well-read Westerners would struggle to identify even a dozen of them. So people selectively remember the ones that involved the major powers (e.g., Afghanistan, Iraq, Vietnam) while completely ignoring ones that don't (so, how about that rebellion in Aceh that failed...).
Because failed ones don't last long enough to be remembered. There was a guerrilla insurgency in Iraq after Saddam's government fell, for example, which folded pretty quick.