Hulu and Netflix's data disagree with you which is why I dsagree with your statement about general audiences. Additionally, you are forgetting the one leg up Comcast has which will be Spanish Language content as the only major distributor with a spanish language production company (Telemundo) which already beats NBC, ABC, Fox, and CBS in total viewers depending on the shows.
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https://www.hulu.com/press/hulu-update/hulus-2018-end-of-yearbook
Law and Order:SVU (NBCUniversal) Today Show (NBCUniversal) and Brookyln 99 (NBCUniversal) were some of the most watched shows. In fact SVU has been on the most watched shows for Hulu for the past 3 years.
And if you are arguing movies, using Hulu data....the most popular were I Tonya, Transformers, and Baywatch....
And the most popular show on the service period is South Park not owned by Warner nor Disney.
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Going to Netflix, unfortunately for movies not owned by them, they don't release data however, other companies got tv data
Netflix’s most popular shows — which are also the shows Netflix could lose - Vox
The most-binged shows and watched movies on Netflix in 2018 | Metro US
Looking at the television list look at the top three: The Office (NBC) Friends (WB) and Parks and Rec both (NBCUniversal).
Look at Netflix's most watched original fims: They are YA romances.
You do know the most popular kid show is Boss Baby right? That's from Netflix's executives.
Netflix renews ‘Mighty Little Bheem,’ reveals growth strategy - Los Angeles Times
And kids in multiple age groups really like the Dreamwork shows
Kidscreen » Archive » Infographic: What are kids’ favorite shows on Netflix?
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Dreamworks Animation has never quite reached the cultural influence as Disney Animation and Warner Bros. Animation throughout history. Yes, some of the DWA movies/TV shows are popular, but those aren't quite as influential in comparison to the groups I mentioned, nor as well known to the general public. Also, NBC's only leg up so far is the Good Place and Brooklyn Nine-Nine. The rest of the NBC shows are not as appealing and mainly music/dance/singing shows. USA Network is always on the weak spot as well, and its well-known show is Mr. Robot, which is going away after it aired its fourth and final season. The network constantly has reruns of Law and Order and its spinoff, which doesn't interest the general audience as much if you're not into police procedural/crime drama type of stuff and prefer something actiony/thriller like Breaking Bad or American Horror Story. Pointing out that some shows are popular for a specific company doesn't mean that the service will sell well since it needs to include a bunch of appealing content to draw people in, like what Disney and WB are doing.
While I can agree Fox had some of the best adult/family animation. The only one going on Disney+ is the Simpsons, despite Bob's Burger being vastly superior in every way. Additionally DC Universe streaming site which was already focused on DC characters underperformed.
Well, no surprise, the Simpsons is one of the most highest-profile TV show of all time and is a highly influential TV show that later paved the way to other adult-animated shows decades later. Bob's Burgers despite being juts as good offers society nothing new to the table and isn't as influential in comparison to the Simpsons. Off course, Disney is going to choose the Simpsons as one of the launching pads for its service. It's no brainer.
While Warner Bros does has some great children gems, most of the beloved shows that defined a generation have ended (Adventure Time, Amazing World of Gumball, Regular Show, Steven Universe, etc) and I'm sorry but they already overdue it with Teen Titans Go which was the most watched family cartoon on Hulu.
While it's true today's cartoons are not as great as they used to be, Disney and WB still have a rich history of animation that leaves a lot to be desired by people who crave for nostalgia. Universal's not so much. WB still has Adult-Swim that airs shows like Robot Chicken, Rick and Morty, Squidbillies, and the like. Disney is now in possession of every Fox adult-animated show ranging from Simpsons to Futurama to Family Guy to Bob's Burger. Odd though, Universal doesn't have a single successful adult-animated series despite being a well-known studio with well-known movies and having the best theme parks in the world. People still have the appetite for adult-animated shows and Universal might want to tap into the market after Netflix heavily invests into it as well.