Genuine question from a non-aviator, having just landed safely at 150kts or whatever the speed was, why is it deemed unsafe to slowly taxi the aircraft far enough clear of the runway so the airport can remain open?
The Boeing QRH has a "Caution" note in the landing gear checklists not to taxi the airplane or use the tiller if you have landed without all the landing gear down. "Caution" notes imply you can damage the aircraft if you don't follow them.