What does "try" mean? Did they actually apply for permits? If so, when?
If the complex management knew there were dangers with the stairs, they were obligated to shore them all up, block them off, or evacuate all upstairs tenants from the premises until such time as the stairs could be repaired/rebuilt.
There was one news story that said a permit was pulled June 16 THIS year. That doesn't really seem reasonable since they already had a collapse LAST year.
Everything you list seems like the reasonable thing to do. I can't understand why it wasn't done as soon as they knew they had problems. I'm thinking these large companies that own a multitude of apartment complexes have their own bureaucracy to get things fixed.
Now they are telling people to only go up staircases one at a time, to hold onto stair rails, and don't carry anything heavy when going up the stairs. Might as well throw in, "learn parkour."
This never should have happened.