Star Trek: Voyager aired January, 1995 to May, 2001. The show was created for a 90's audience. Back then, most shows were episodic wirh character arcs instead of story arcs. Some shows were beginning the trend of story arcs like The X Files, DS9, and Stargate SG-1, but it wasn't common. I think Brannon Braga wantwd the Year of Hell to span most of the fourth season. The network, UPN, wanted it to be a two-parter. Back in the 80's and 90's, a show relied heavily on reruns to recoup from the cost of initially creating the show, such as the building of the expensive sets and what not. UPN wanted the show formatted so reruns could be shown in random order.
The network didn't even like two-parters. Out of about 170 episodes, we only got about a dozen two-parters.
Where the network chilled out was "follow up" episodes to older episodes. So, we got a lot of those.