There's no way that at current level of technology any game will ever archive the success of Skyrim even TES6- Skyrim launched at perfect moment when there was not that many open world games to compete with, in the middle of one of the most accessible and popular console generation, when people where going apeshit over Game of Thrones and wanted more fantasy stuff and when Bethesda was that cool studio which couldn't make a bad game and people were more tolerant of Todd's exxaggerations.

The only game which might be able to archive something simmilar to Skyrim will be the first or one of the first big scale RPGs for VR when it become more accessible and cheap enough that it won't be treated as technological curiosity for people with too much money and space in their house, for now there's no way that any stricte single player game made for current style of gaming will ever archive something close to what Bethesda did in 2012.