i thought it was established in Tapestry he commanded the ship for like 22 years or something...
That was from the writers' bible, but it was never made explicit onscreen. All "Tapestry" said was that Picard "[took] charge of the Stargazer
's bridge when its captain was killed."
In fact, what the writers' bible said was that he "served on an incredible 22 year voyage as mission commander and ship captain on the legendary deep space charting vessel U.S.S. Stargazer
." Which, to me, doesn't explicitly say he was the captain for the entire 22 years, because "mission commander" sounds like a different job title. Although of course the Stargazer
novels interpreted it to mean that he was the captain for the full time.
I was always under the impression that Picard's command of the Stargazer was a big deal. I swear there were several times were we heard people talking about Picard and the ship like it was a big deal.
That seems to be another case where something from offscreen backstory is misremembered as onscreen material. It was only referred to as his "old ship" a couple of times, and occasional reference was made to specific missions aboard her (for instance in "Chain of Command") and to Jack Crusher's tenure aboard her (for instance in "Family" and "Menage a Troi").
At least, that's what I can find in my Google search of the script site. But I think that search is incomplete, because when I told it to search that domain for the word "Stargazer," it didn't turn up any hits from "The Battle"! So it may be overlooking a few references.