You're right. But you might have skipped over some good bits. He also says that Bethesda has consistently revealed in every next Elder Scrolls game what happened to the previous main character in a turn of events that result only from main storylines (which are 100% canon, as opposed to arbitrary quests like joining/destroying the Dark Brotherhood). Since Skyrim's Dragonborn DLC storyline seems to show the most potential for damnable consequences, we might very well learn of his imprisonment in Apocrypha in Elder Scrolls 6. Also, it's been revealed that the Nerevarine was still afflicted with the Corprus disease and became immortal, and the Hero of Kvatch became Sheogorath, so I guess what I'm saying is, holy crap, all three heroes of the main Elder Scrolls games might still be alive when TES 6 comes out. I just looked up the wiki myself, having forgotten the details you mentioned regarding the Skaal knowledge. Bit of a letdown, actually, which is probably why I forgot what they were in the first place, but I found something else too: "Vahlok defeated Miraak, but just as he prepared to deliver the killing blow, Hermaeus Mora snatched away and saved his champion." Apparently, Miraak was also initially allowed to roam free before Mora got worried about his safety, or something like that. So I think it's definitely a possibility that the current Dragonborn could be locked up sooner or later.