Without Superman comic books there wouldn't have been Batman comic books. Or Wonder Woman comic books. Or Captain Marvel comic books. Or likely no other superhero comic books. Or this website.
Without Nash Bridges, would there ever have been a reason to watch television?
Mostly not serious, but somehow that show had Carlton Cuse, Damon Lindelof, Shawn Ryan, and Glen Mazzara. Lost and everything that follows fro, that. The Shield, which starts the FX ball rolling, then Kurt Sutter comes out of the Shield...
Without The Dark Knight Returns we wouldn't have DC revolving around Batman.
Without "Jaws," there would likely be no genre of killer animal movies.
Without Mad About You, there wouldn't have been the film, Sex Tape (which is basically an episode of Mad About You).
Without DS9, there wouldn't have been the film, The Village (which is basically an episode of DS9).
Without the BBC there never would have been a million inferior US programme remakes.
Without the X-Files there wouldn't be any of the great serialized shows we have today. Before the X-Files all TV was largely made up of stand alone episodes so that viewers wouldn't need any backstory to enjoy the episode. The X-Files changed all that and showed that a semi serialized show could work.
The spotlight was on them the year before with From the Earth to the Moon. That was the mini-series from Tom Hanks, Ron Howard, and Brian Grazer just a few years after Apollo 13. Same kind of thing with Sex and the City, when that show first came one HBO it was huge, it was being talked about everywhere. I would actually think that without From the Earth to the Moon you don't get Game of Thrones...maybe. That series is probably the reason Steven Spielberg and Tom Hanks do Band of Brothers there a few years later, and Mike Nichols does Angels in America after that; and those are probably why John Milius goes there to do Rome as a mini-series.
Why won't you ever see an episode of The Sopranos. It's like one of the best tv shows ever made...like it really is, that isn't just the kind of dumb hyperbole you hear every time a new show comes on cable.
Showtime had a number of big talked about shows before Dexter. I'm not really sure Dexter said things were really different either; I mean, I watched that first season on CBS, and it fit right in with the network that brought you CSI. Actually a bit surprised they didn't keep showing it on CBS. At most, around that time was when it did seem like Showtime was going to try getting into original programming in a bigger way though.
Without James Bond, no...
Man/Girl From Uncle
SHIELD (and a wholly different MCU)
Get Smart
Without Star Trek no cell phones. The flip phone was inspired by TNG's communicators.
Without John Carter of Mars, there would have been no Star Wars (Lucas reportedly started working on an alternative when he couldn't acquire Flash Gordon, Flash Gordon was created when Burroughs wouldn't license John Carter for the newspapers, who wanted a competitor to cash in on Buck Rogers' schtick).