Generally speaking, I think two things went wrong here.

1. Almost anyone seeing all the warning signs probably didn’t think an entire building could collapse or partially collapse. Things could look terrible, but maybe not enough to say, “I need to get out of here before this building collapses.” Yes, that is said in old building and homes but it just doesn’t compute in building this size. That is why a professional inspector needed to be involved.

2. Time was also a problem here. In the US, a modern city with a 40 year old building just doesn’t compute. It’s actually kind of old in the US, especially with problems like this. Similar to #1, it didn’t compute a building this size could collapse this way. That is why a professional inspector needed to be involved.