re: What should the USA have done after 11 September 2001?

Point well taken.

Even now, it can be argued with great persuasiveness that Obama's attacks on ISIL will "just create more terrorists".

There is no doubt in any reasonable person's mind that the US drone offensive against terrorists is indeed creating "more terrorists" due to the unavoidable and occasional casualties such attacks inflict on innocents.

I guess that Bush thought that invading Iraq might create a new US ally in the region and operate to eliminate AQ and future risings of AQ organizations.

It would make sense to find a permanent solution like that. The reality seems more grim in that the US is going to have to keep fighting Islamic terrorists forever. They are not going away, whether we try to give them hugs or slugs, they are not going away ever.

So, the US electorate is going to have to deal with this fact.