It was. Exacerbate that is. Give it some thought. It was also calculated to show the collection of nations from which the threat originates that attacks on US interests world wide emanating from the ME would, contrary to previous experience, bring a disproportionate response. As Afghanistan had earlier shown that attacks on US soil would be met with even swifter and possibly more disproportionate response. Afghanistan didn't work for the ME message as it isn't in the ME.
This might have worked if the insurgency had not broken out. Instead it gave us five years of jihadist propaganda and videos of American hummvees exploding. It made for very poor intimidation if your target was the wider Middle Eastern populace. With regards to state actors, I doubt it made much of a difference. Iran certainly did not intimidate well - it was not long before they were killing Americans with far greater success and frequency than even the worst years in Lebanon. Syria's ties with Iran are tighter than ever, and Turkey as well. Certainly anti-Americanism in the region is as strong or stronger than ever before.

As for the invisible effects, I suppose it's a bit difficult to ever argue that point. Perhaps great benefits are accruing out of sight. I suppose you could say that about any policy.