Think about it... you just spent 50 years in the Nexus, thinking you'd been released five decades ago, then someone comes and pulls you out...
Would you even believe them? Or would you convince yourself you were *still* in the Nexus? I mean, for it to be believable, you have to grow old - and the Nexus can only pull that Insurrection damaging trick so many times before you get suspicious. So, when you age 50 more years, the Nexus is all "Oh, no, lol... here, you're free this time. wink wink. ****. I wasn't supposed to say wink. Sorry. New to this. You're free now. Promise."