It would seem that Jean-Luc Picard did not take the advice of James T. Kirk. When the two of them went horseback riding in Star Trek: Generations, Kirk (William Shatner) urged Picard (Patrick Stewart) not to retire. "Don't," he said. "Don't let them promote you. Don't let them transfer you. Don't let them do anything that takes you off the bridge of that ship, because while you're there, you can make a difference."
At no point in this exchange does Kirk say, "...unless you feel like kicking back on your family's vineyard for the rest of your life."
Star Trek: Picard has us returning to the world of Jean-Luc, and in the time period of the new series, he has left Starfleet. Not only is it something that Kirk flat-out told him to not do, but it's also something that we never thought would happen. There must be more to it than Picard seizing his "big chance to get away from it all," and the new trailer might give a hint or two.
Why would Jean-Luc Picard leave Starfleet? We have some theories.
IRUMODIC SYNDROME HAS STRUCK
In the finale of Star Trek: The Next Generation, Picard flashes forward to an alternate version of his future where he has a disease that affects his mind and mental capabilities. He's no longer involved in Starfleet because this illness has taken a toll.
When back in the present, he asks Dr. Crusher to scan for signs of it. She doesn't find any, but she does find a potential defect that might cause it someday. Over the course of four movies with the good captain, we never heard about this illness again, and for all we know it was just another merry little detail in Q's not-so-merry game. Still, was the defect real, and has it caused the Irumodic Syndrome to manifest in Picard at long last?
He doesn't look sick or befuddled in the trailer, but it's still a possibility.
WELL AND TRULY BORGED
Did Picard ever fully get over his Borg assimilation? He did take some time to heal after those events (TNG: "Family") and revisited them in the episodes "I, Borg", "Descent, Parts 1 and 2," and really went back to them in the film Star Trek: First Contact.
For something as traumatic as this, though? Having your individuality erased, and being shuffled into the Borg collective consciousness is not just something that can be hand-waved away with a few Counselor Troi therapy sessions. The opening space battle of First Contact seems to indicate that Picard still has some kind of link (or hidden knowledge) about the Borg... we're guessing that the events of the historic "The Best of Both Worlds" two-parter are events that don't ever really leave you.
Whether this was the reason for his leaving or not, his experiences with the Borg are sure to be visited once more — Hugh (from the TNG episode "I, Borg") will be on the new series, as will one of Trek's most famous Borg — Seven of Nine ( or Annika Hansen) from Star Trek: Voyager. Fun is sure to commence.
The trailer directly has Picard talking about Data sacrificing himself for him during the last movie that we saw them all in, Star Trek: Nemesis. The crew seemed to get over Data's loss fairly quickly, and after a glass (or two) of Chateau Picard, everyone went back to their own lives. Way to soldier forth, Riker!
Is the loss of his friend still hanging over Picard? Is it hanging over him to such an extent where the guilt is so huge that he can't bring himself to slap that uniform back on? We see a disassembled Data-like figure in the trailer, but this is likely B-4, Data's less-than-great predecessor who may or may not have some of Data's memories.
Data himself appears at the end of the trailer, and he's fully assembled. Brent Spiner has said that this is not B-4, that he is fully playing Data in this scene, as well as the show as a whole. How is that possible if we saw Data explode? Perhaps Picard has taken a page out of Gaius Baltar's book, and he now sees a Data in his head. Perhaps his guilt over losing his friend has somehow mixed with residual Borg energy, and a "Head-Data" has begun to be a thing! Don't roll those eyes, Trek has done far weirder things than that. Allamaraine!
If Caprica Six ends up dealing herself into their card game, then we'll know that we have some head games going on…and more than a few problems.
The 2009 film Star Trek has its timeline rebooted because of one very angry Romulan going back in time to get some revenge. This Romulan, named Nero, is after Spock... who he blames him for the destruction of the entire planet of Romulus.
Spock was involved in trying to save Romulus, but try reasoning with Nero! Also involved with the efforts to save Romulus? Jean-Luc Picard... at least according to the tie-in comic, Star Trek: Countdown. Both Picard (and a Data-infused B-4) were trying to save Romulus in this may-or-may-not-be canon comic, and if they stick with this history, then Picard would likely feel pretty bad about not being able to save the day.
Yeah, Romulans are generally horrible, but if Picard ended up being unable (or even complicit) in the destruction of their homeworld, he'd blame himself mercilessly for it. The loss of an entire world would be a blow to Picard's savior complex, and we could see that getting him to box his combadge for good.
ALL (NOT VERY) GOOD THINGS…
Our final theory? It wasn't just one thing that drove Picard away from adventure... it was a potent mix of this entire list, creating a brew that would knock Guinan down to the floor of Ten Forward.
Let's say that the show runs with the current (assumed) canon of Picard being involved with the destruction of Romulus. Guilt over that? Check. Lingering guilt about Data's death? Another Check. Very much not over the Borg thing, and likely never will be? Check check. Throw in a last-minute diagnosis of Irumodic Syndrome, and we're guessing that even Captain Kirk wouldn't begrudge Jean-Luc his season pass back to vine-ville. This is a man who has lived two full lifetimes, after all, as seen in "The Inner Light," when he lived an entire existence as "Kamin." Picard's earned some retirement twice-over.
It could also have been because of something that we don't know about yet, for all we know. Perhaps he was "encouraged" to leave by Starfleet Command. We're curious if he ever became an Admiral before he leaving. It was good enough for Janeway, after all.
Whatever the reason was, we're going to find out when Star Trek: Picard debuts in later 2019. He may not be rejoining Starfleet, but Jean-Luc Picard is going back to the stars. As he says in the trailer, he's "not ready for the game to end."
The sky is still very much the limit.