MS
1%er
The point is that the NFL almost never has a QB go through college, the NFL draft process, go undrafted, and then not even catch on a practice squad somewhere.. and then go to be a difference-maker in the league. Whatever weird counterpoint you are trying to make about the NFL not scouting players in countries around the world is completely meaningless and quite obviously has no application to the player we are talking about.
I would say that this isn't as much that it *can't* happen as that the system and the way the NFL works makes it very difficult to happen.
There are basically 3 types of NFL QB : 1) The Established Stars, 2) The Hot-Shot First Round Pick, and 3) The Trusted Journeyman (who used to be (1) or (2)).
Teams without an Established Star will always be going with one of the other two options. It is exceedingly difficult for an outsider to 'break the ranks' to get the playing time to establish themselves, and usually requires a unique set of circumstances to happen.