Why was a plane with hydraulic problems not stopped at the end of the runway?
The plane landed safely but lost complete hydraulics en route to the terminals. They are lucky to hit the other plane rather than the immovable building.
Occam's Razor.
Probably because the problem hadn't manifested itself yet.
Otherwise the plane would have run off the end of the runway.
D'OH!
If every airplane that had a problem of some sort on take-off or landing were to be stopped at the end the runway, you'd turn every major airport in the world into a used airplane lot.
Most likely there was no indication that the redundant system was going to also fail. There are very few single points of failure on an aircraft, but there are some. If when the pilots landed, the necessary systems were functioning ie brakes and steering, they probably figured they were safe to get to the gate.
It will be interesting to see the report that tells just where the failure was.