In those cases the court found the intent manifest in the language. These were sophisticated parties with legal advice. Even if they court didn't see intent, it is within the courts' power to force such persons to follow the language if for nothing else than to serve as example to other negligent contract drafters.
A court will only grant that which is asked for. So for a typo to matter, one of the two parties before the court must be claiming that is isn't a typo.
