They subcontract different parts of the project to different companies who will rarely if ever communicate with each other.
Very often company B’s ability to complete task Y is dependent on company A finishing task X. Company B turns up, sees that company A has not finished task X and says ‘fuck it, we were paid to do task Y and we’re bloody well going to do it’. So they do it, incorrectly, knowing full well that all they have done is cause problems for everyone involved.
Then company A does turn up, says ‘what’s all this shit doing here, company B was supposed to wait for us. Now we need to hire company C to clean this shit up so we can do our job!’ And so it goes, the jobs are done over and over and over and over again until by chance, by accident, or by coincidence, they are done in the right order.
This is generally stupid shit like ‘installing’ the servers before the racks turn up, furnishing rooms before they’ve been carpeted, or getting the roofer to turn up before you’ve laid any foundations. And he WILL build you a roof, make no mistake about it. “I’m just doing my job” is the 21st century get out of jail free card.
And it happens in every fucking government project going.