The engineers learned from Scotty. There was a great scene in TNG where Scotty reveals to Geordi the estimates were rigged all along.

But then again, it’s a TV show designed to produce tension. Star Trek: Drydock wouldn’t be as exciting. But anyone who’s ever worked with ship’s equipment knows, it’s a lot of fun to test missile launches. Cleaning those tubes, however, not so much.

A few shows have spoken to the likely realities of maintenance. The Expanse and Battlestar Galactica didn’t hand wave the logistics and maintenance such vessels would certainly require.