I agree the outcome of the wars in Afghanistan and Iraq could have been better. In fact I would even agree they were disastrous. But:

If we had nuked Afghanistan we (probably) would have kicked off WWIII.

If we had done nothing further attacks may have occurred.

Both of those seem at least worse than what actually happened.

imo, there's no possible world where not invading Afghanistan causes 2 trillion dollars of attacks. (especially because 9/11 had only very weak links to Afghanistan)