Geez... Project managers are forbidden from making work estimates- they only get to collect them.
They don't get to argue estimates either. They can ask questions to gain understanding but the estimates are the estimates.
Wearing an architect or chief engineer hat is sometimes more fun because you get to call bullshit on dumb estimates like "4 to 5 weeks to model a table with 7 fields, with 2 of them being PK, FK" like GTFO we can model it in the next 5 minutes if I talk slowly.
I blame lean philosophy. Keeping spare parts and redundancy is expensive so definitely don't do it...which is just rolling the dice until it comes up snake eyes and your plant shuts down.
It's the "save 5% yearly and stop trying to avoid a daily 5% chance of disaster"
Over prepared is silly, but so is under prepared.
They were under prepared.