Executives at both CBS and Viacom are optimistic about the benefits of a pairing. While they don't have the iconic brands of Disney or Warner Bros., together they still would have strong assets for a solid direct-to-consumer streaming offering.
CBS has already made some headway in that arena with its "All Access" platform, which has about 4 million subscribers and successful shows including "The Good Fight" and "Star Trek: Discovery." CBS's Showtime streaming service also has 4 million subscribers. CBS has said the two services combined will reach 25 million consumers by 2022. Viacom says its ad-supported Pluto TV service has 18 million monthly active users.
The addition of Viacom's cable networks such as Comedy Central and Nickelodeon and movies from Paramount Pictures' library could enhance All Access, people close to the companies said. CBS has already said it is adding children's programming to the digital platform.
At the same time, there is concern at CBS that adding Viacom content into CBS All Access would significantly raise its cost, a person familiar with the situation said. All Access costs $5.99 a month with ads, and $9.99 a month without them.
In the traditional cable TV business, Viacom and CBS hope that together they'll have a stronger bargaining position with distributors, which are increasingly looking to rein in programming fees as they lose subscribers.
For CBS and Viacom, "coming together in 2019 is the right thing to do, but the question is does it matter at this point," said a former Viacom network chief.
Breaking down fiefs inside CBS and Viacom so they can truly join forces will be challenging.
"Bob won't let whoever runs CBS run his own little shop," said another former Viacom senior executive, referring to Mr. Bakish.
A person close to Mr. Bakish said that when he started as acting CEO of Viacom, he immediately set about trying to break down silos between divisions and repairing the company's frayed relationship with pay-TV distributors.
There are promising opportunities in joining up the CBS Television Studios unit and Paramount Television, including the expansive library a combined company would have, from "Star Trek" to "Dora the Explorer" to "Survivor."
The studios share a similar strategy: Beyond producing for their in-house networks, they also produce actively for outside platforms including streaming giants.
CBS has made successful shows for Netflix including the new comedy "Dead to Me" and has shows in development at Apple and Disney's Disney+ streaming service. Paramount made the teen drama "13 Reasons Why" for Netflix and "Jack Ryan" for Amazon.
As Disney and Warner Bros. focus increasingly on making content for their own television and streaming platforms -- part of a trend of vertical integration in Hollywood -- a combined CBS-Paramount studio could become a go-to supplier for rival TV networks and streaming services.
Write to Benjamin Mullin at Benjamin.Mullin@wsj.com and Joe Flint at firstname.lastname@example.org