It's hard for me to say, because I'm not invested in series like that, so the closest I've been is an author saying "it'll take three years" and it comes out in three years.
There is a dialectic you have to maintain. First, yes it does suck and you have a right to feel that way. Second, you have to understand you aren't entitled to a complete series. You have no contact, implied or explicit, that the author owes you the next installment in a timely manner.
While those two concepts combat each other in a Hegelian death/ life match: find new books and read them. If you have plenty to occupy your attention, the authors being total dweebs all of a sudden does not matter too much.