There is something I’ve read more than once from authors about ”not starting unfinished series;” one of the problems is, sometimes the contracts they’re working under stipulate that if there isn’t enough interest in the first books, the publisher isn’t required to order up sequels. (Not in the publishing industry myself, so I don’t know how the details work.) So, if enough people refuse to read a series before it‘s finished, that becomes WHY it never gets finished. While this probably doesn’t apply to authors who are already super-successful like Martin or Rothfuss, it’s food for thought. Support the authors you love when they start new series.