
you had better uninstall Total War then as there are tons of beneficial features that don't apply to the ai, or rather benefits that are player only.
Why do you think it is impossible to lose. It's not just down to AI intelligence, of which there is actually none. AI does not even have a memory. If the AI answered its door each day and someone punched it in the face it would continue to open the door each day, it would just be more angry with you without knowing why. If the AI saw you running round its garden with an axe it would prepare to attack you, but if later on it could not see you it would forget you were there at all.
My feeling is that originally the "AI" was powerful enough to take down a player mostly by brute force, but then the writers (probably correctly) decided that most players would not actually like to lose a campaign but rather explore through it, inevitably conquering, imagining themselves as strategic and tactical geniuses. From there it was either an inability to apply most of the features that allow a human player to win easily to the "AI" or an intended neglect to keep the "AI" down. You play a few factions then buy the next game. That's just good business.
I'm not one of the players that enjoy winning artificially.
The "AI" offers the illusion of intelligence and BGR offers the illusion of other medieval factors that are otherwise missing from the game and tries to offer the player a challenge through their application.