All shows have arcs, whether they're episodic or arc-based. It's inherent to the medium of television series, or for that matter any fiction series with fixed continuity, be it magazine serials or comic books or movie series. Arc-based shows are simply shows with a more conscious attempt to acknowledge the arcs in their own show. It's mostly in the past decade that Arc-based shows have gone mainstream.
I think reasons that studios might find that stuff more commercial now include TV on DVD box sets, reality television (which as much as I dislike it does train viewers to tune in week-to-week to follow a continuing storyline. Reality TV, along with NYPD Blue and French New Wave cinema verite, also probably account for the prevalence of hand-held camera-work in todays TV and movies.), and shows like Hill Street Blues and DS9 being shows of which current TV producers grew up watching.
The pendulum probably won't swing back in that regard, simply because this is a step in the evolution of the medium, not television reverting to some previous trend.
I think reasons that studios might find that stuff more commercial now include TV on DVD box sets, reality television (which as much as I dislike it does train viewers to tune in week-to-week to follow a continuing storyline. Reality TV, along with NYPD Blue and French New Wave cinema verite, also probably account for the prevalence of hand-held camera-work in todays TV and movies.), and shows like Hill Street Blues and DS9 being shows of which current TV producers grew up watching.
The pendulum probably won't swing back in that regard, simply because this is a step in the evolution of the medium, not television reverting to some previous trend.