Business 101 ...
That's even worse! Putting up a portion of a set and then waiting 4yrs to put up the rest is insane. That's like posting a sex scene and waiting 4yrs to finally show the pop shot. lol!
So, business 101 here.
Would you rather pay monthly?
Or pay by the set?
If the latter, then yeah, sites could release things all-at-once, pay as you download.
But in reality, most people would rather spread their payments over a subscription.
So the common approach is to shoot now, release periodically.
It's been the common approach for years, both pre and post-Internet for publications.
Either way, the consumer pays.
There is no correct way, just common approaches, in a sustainable, business model.