"In any case, the names of the twelve sons of Jacob do not quite correspond to the names of the tribal areas, which is pretty hard to explain if the sons were invented based on the areas. "

All the above is said in fun and jest, but just out of curiousity...

I agree with your Occam's razor point. But even more...you're not saying that the names of the tribes don't match up with the sons of Jacob when taken in consideration that the sons of Joseph (Ephraim and Manasah) make up the only two tribal names that aren't directly (first generation) sons of Jacob, are you?