Silly, Dan.
They "will" come down, entropy you know.
They are not "designed" to come down. Last thing on the architects minds.
The one that started to lean did so because the floor structures outside vertical structural members on one side, the side away from the collision, gave way. The weight where it started to lean collapsed the floor structure aacross the building, and it came down.
Not by design. Talk to an architect. Really.
Arf