how could we gauge how steady progress has been vs how it was supposed to progress to meet the original deadline? a project of this scale would have a very complex schedule that would be part of the contract documents, no one just commits to a date without a ton of asterisks, and a contractor who has been in business a while is a master at documenting every delay religiously. there are many different trades working, some independent and some not. "progress" could be made in some areas while a different path is being pushed back a couple weeks and we wouldnt know. a partial delivery of some material could cause a sub to justifiably only put half the workforce on this project, that's still "progress" but off schedule. not to mention external delays ( cant get such and such inspection because some office has Covid going around, etc)
the project may have never sat with nothing done for 2 months at a time but multiple 1-2 week delays on certain paths would be impossible for us to see and still end up as months on the final product.