It's possible to just be unlucky. It's also possible to be your best while not being quite as good as a couple of better-resourced clubs. What if we're a 20% chance of winning the comp this year? Are we failures if we don't win? It means we're an 80% chance of not winning, so hardly a failure if it doesn't happen.
Obviously you'd like to be a 20% chance (or better) of winning the comp every year but it doesn't seem possible for most clubs. Do you mortgage the future to get another year of being a solid chance (about 1 in 5, IMO) and then follow it with four or five years of almost zero chance (maybe 1 in 50)? If your 20% chance works out and you win the comp (like the 2016 Sharks) then yes, the fans will accept just making up the numbers in the following years.
But if you don't win (which is more likely even when your premiership chance is 20%) the recruitment/retention decisions won't have been any different than if you'd won. But idiot fans won't see it. Because they think there is no luck involved, even if they're punters and should know better.