There's only one way that any of this would make sense: That Kirk actually did die on the Enterprise-B like everyone thought he did, and that everything Picard experienced in the Nexus, including his visit with echo-Guinan and then Kirk, was all just part of the Nexus-induced fantasy, and that Picard is still in there.
Let's review this a little. On the Enterprise, Guinan tells Picard that the Nexus is so addictive that he'll never want to leave. The movie then later shows the complete opposite of this: That Picard and Kirk are able to leave it just fine after realizing that their respective fantasies are just that, fantasies. But what if the Nexus was just compensating for the fact that Picard's family fantasy wasn't working? What if it created the false Guinan in an attempt to fool him into thinking he could leave? And then the false Guinan leads Picard to believe that Kirk was also trapped in the Nexus (because Kirk was on Picard's mind when Riker mentioned the Enterprise-B to him earlier in the story), and creates a new fantasy where Picard meets Kirk, convinces him to leave the Nexus with him to go back to the real world to stop Soran (which doesn't actually happen), and completely glosses over the fact that Picard picks the absolute worst point in time to go back to? He then defeats Soran, saves the planet and his crew, and witnesses Kirk's death because the Nexus fantasy no longer needs him. Then in the next three films Picard becomes an action hero (like Kirk) despite this being totally out of character for him, fighting Borg, going back in time to meet Zefram Cochrane, kicking Son'a ass, and finding out he had an 18 year old evil clone all this time, and kicking his ass too. Not to mention his hijinks in Star Trek: Picard.
Despite the fact that it's all just a Nexus-induced fantasy.
Unfortunately, of course, this would also mean that Soran was successful in destroying Veridian III, along with killing the entire Enterprise-D crew. And anything we see on screen after that, which includes over half of DS9 and all of VOY (especially Worf on DS9, Troi and Barclay on Voyager, etc.,) is also just part of Picard's Nexus fantasy, since all of the Ent-D crew are dead.
Mind blown?