There's something wonderful about the really long, immersive experience of long-form art.
These exist in many genres: whether that's a series of books like Patrick O'Brien's Aubery/Maturin sea saga (more a single multi-volume novel than a series of sequels) or Lois McMaster Bujold's similarly multi-volume Vorkosign series in science fiction. Bujold says the multi-volume form is distinct from the standard novel; I tend to agree - just as the short story is distinct from the novel, or the ode from the epic poem. Sprint versus run versus marathon. The TV version might be a miniseries like Roots or, more extended, a mythologically dense long-term series like Buffy the Vampire Slayer. And there are operas, like The Magic Flute, and operas, like Wagner's Ring Cycle. Personally, I enjoy the long-form, but I'll admit that some of its satisfaction comes from making it through the whole thing!
The cover of Ace's LotR, center of a copyright dispute
I think creators have a natural pace and style... and some need time and elbow room.