The Elder Scrolls spoke of this.
Whatever your thoughts on the Elder Scrolls storylines, the fact remains that they exist, and that they dictate the direction Bethesda choose for subsequent games in the franchise. That, coupled with the fact that Bethesda have at this point apparently opted to visit a different, new province of Tamriel with each new installment, means that their hands are increasingly tied with each new game- they are running out of provinces to make games on, and they have to maintain continuity with an increasing number of games.
Therefore, the question of Bethesda possibly rebooting the entire franchise with the new game, The Elder Scrolls 6, now confirmed to be in development by franchise director Todd Howard, is not an impertinent one. Rebooting the franchise means Bethesda no longer have to be cognizant of their entire continuity- some of it stretching back to two decades ago, to games made in the early 1990s, reflecting creative decisions that the team may not even hold to now, made by people who may not even be a part of Bethesda any more.
It also means that Bethesda are free to explore some of Tamriel’s more interesting geography with modern technology. Imagine a game like Daggerfall or Arena, but with all the power of a console like the upcoming Xbox One Scorpio! Or, better still, imagine a game that, like Arena in 1994, allows you to traverse all of Tamriel!
That is a game I would like to play- and therefore, that is a game that I would not mind being made. If that necessitates a full and total reboot of the franchise with the next game, then so be it- I don’t have much love lost for the series’ narrative so far anyway. Their lore and mythos, yes, but those would be maintained in the reboot regardless. It’s just their narrative continuity that I don’t care for.
I imagine there are very few people who do, in the end, and so, I don’t think this is necessarily a forbidden path for Bethesda when it comes to The Elder Scrolls 6.