Those examples are too old to be very useful. TV is changing fast, which may be in Star Trek
's favor since broadcast is under extreme pressure to adapt to the future of narrowcasting exemplified by Amazon and Netflix (without having subscription revenues). Cable is also starting to feel the pressure.
The more the industry shifts towards narrowcasting (smaller audiences paying more for nichier content), the better it is for Star Trek
which is in a niche (space opera) too small to work on broadcast and even basic cable is questionable anymore.
Premium cable might be able to swing it, but they'd be more likely to follow the Game of Thrones
model and adapt some well-regarded novel series vs. going with a brand associated with free TV (not really the image Showtime wants to maintain - brand image being totally separate from the quality of the program itself.)
CBS is the most secure of all the broadcast networks, so they're under the least pressure to swing for the fences. Conversely, being in the more secure position, they might feel more free to experiment with new ways of delivering nichier content, like their collaboration with Amazon to produce Under the Dome
(definitely genre, unlike Person of Interest
, which is sci fi only under the most generous definition.)