If bin Laden's victory condition was "many overly-reductive Americans bemoaning negative events in their nation's existence by parroting that the sky is irreversibly falling, throwing in the entire towel, forgetting or never bothering to study several existential threats to the United States in its brief history, and shrugging that our doom is all due to a Big Bad who managed to take down the world's occasionally most powerful nation with four airliners," then sure, he won. Since it wasn't, your comment is pretty much meaningless despite its appearance of wisdom.
It's weird, for all this terminal rhetoric I read about the end of America I still drove to work this morning and still had faith in American values, not to mention a crazy belief that what's right will ultimately prevail in the face of great adversity. What's more, I feel uniquely empowered as an American to roll up my sleeves and create the America I want to see and believe is good for the rest of us, and I didn't even need Gandhi to teach me that one.
I guess I need a sandwich board instead, because what's the point? Are we merely South Canada now, waiting for an eventual invasion that will take our economic, military, scientific and cultural leadership away, leaving a skeleton of a sovereign state that barely made it out of puberty? What coffin do you think Trump is building? I'm about as disapproving of the current administration as you can get, but I've also studied just enough of the world to understand that things tend to endure, even when the situation looks most hopeless to all involved.
Look at the Big Bads that the British survived throughout their centuries of history. Sure, Pax Britannica and their colonial adventures around the world have come to a close, but I don't see any comments saying "the world won, Britain lost, might as well yield the Crown and just absorb into the EU." Nope: they still fight for what they believe to be good and properly British, including giving the finger to the rest of Europe when they feel it necessary. We should learn from that example, of those with the learned memory of an empire from which they descend, deflated by the world changing around it, yet avoiding the adoption of a fatalist nostalgia that impedes all progress and hope for the future.
If the British aren't a good example, look at the Germans who still live in the punchline of uncomfortable jokes. They're still here, still making some mean beer, and still a valuable member of the world. Not even a particularly misguided government pissing off the entire planet could get rid of a German ideal that lived in its citizens' hearts, and they had a God damned wall down the middle in the wake of that mess to constantly remind them of how hopeless it got.
We are due to be knocked down a couple more pegs than we already are. If you're of the mind to give up when that happens, then you can identify yourself as a member of the "winning" army. Saying UbL won and giving up makes him win. How do you not see that?