Then they fixed Artoo up by pulling an all nighter? 😉

It’s also possible Tarkin wanted to hog all the glory, and kept a blackout on where they were going. The question of why the Imperial Navy didn’t show up soon after was addressed in the Marvel comic. The Empire was trying to conceal that their biggest weapon went kaboom, and massive fleet movements would betray something was amiss.

ESB certainly proved the Rebels could take out a stardestroyer or two while bugging out.

The simplest explanation is Star Wars was originally intended as a standalone film.