I think that makes little sense. Statistically, most writers finish the series they wrote. Rothfuss and Martin belong to the rare exceptions to that rule.

So I will have no problem starting series that are not finished. Most of the time those series will eventually be finished, and in the few cases where the series is left unfinished because the author had a burn-out or suddenly dropped dead, then that is just bad luck, so I will just move on and read other series. The only exception I make is when I know for sure that the series will never be finished, which is one of the reasons I will never read the Name of the Wind or Game of Thrones or Berserk.

If anything, I find the way Martin and Rothfuss are still such big names in the fantasy genre despite never finishing their series and never publishing anything else afterwards quite puzzling. Their fans seem amazingly dedicated. I would have stopped waiting for the next book and moved on a long time ago in their place.