Yes, they should all have taken actions. But also, it is much more difficult to fix something broken once the damage has settled in. I guess none of them was willing to risk the disruption a fix would have caused. And the system seemed to have held up for quite a while. Weren't there some mass firings of ATC personal at the beginning of the Trump presidency?
The bottom line is: don't break things that are difficult or impossible to fix.
Absolutely. But for many things, denial is easier than fixing. See climate change. We knew about the problem for a long time. At latest after the oil crisis in the early 70ies, it would have been the perfect moment to reduce fossil fuel usage. Of course we know, how this has not happened and so we just entered the next oil crisis last week. And everyone is to blame for that.
The bottom line is: don't break things that are difficult or impossible to fix.