Yup. Live sports is the "killer app" supporting the linear cable channel system and that will likely be the case for at least a few more years.
We're going to see increasing overlap of the content available in the SVOD world vs. the cable bundle. (The first wave of that happened when HBO, Showtime and Starz moved from being purely cable channels to being hybrid services that also offered all their content via standalone OTT SVODs.) Both sides will feature a lot of the same new entertainment shows, although a given episode might debut on one side a day or so before debuting on the other.
But each side will also have certain exclusives that the other side doesn't have. On the SVOD side, we'll always see various entertainment series and movies (whether scripted or docu/reality) that aren't on cable TV -- think of all that fresh original content that is and always will be exclusively on Netflix, Hulu, Prime Video, CBS AA, HBO+, etc. You're not gonna see Stranger Things or The Handmaid's Tale on any cable channel.
On the cable bundle side, the great majority of pro and top-level college sports will remain exclusive to cable channels. I do expect, over time, to see increasing bits and pieces of live sports become available through standalone OTT services such as ESPN+ but I think it'll take years for the dam to break, at which point basically all sports will be able to be viewed live through some subscription app or another. ESPN+ is clearly Disney's lifeboat for the day that happens. Right now, they're just testing the waters but they'll be ready to sell the entire ESPN live and on-demand content bundle as an OTT standalone service through that app when the day comes. Will be interesting to see if Sinclair, after they finish the acquisition of all those RSN cable channels, decides to offer them as OTT standalones, maybe priced at $10/mo each.
The other thing that I think will prop up the cable bundle besides sports is live feeds of the primetime "talking head" opinion shows on Fox News, MSNBC and CNN. Live news channels are already moving to OTT; CBSN and the Cheddar channels were born in the OTT world (although they're getting added to some cable channel bundles now) as free ad-supported services. ABC News now has something along those lines inside The Roku Channel. NBC News is getting ready to launch their own OTT competitor to CBSN any day now, reportedly named NBC News Now. It's easy to imagine CNN following suit and offering a free OTT news source at some point too, taking advantage of AT&T's Xandr targeted ad platform.
But what you're not going to see on this new NBC News free OTT channel are their popular MSNBC primetime talking heads (Maddow, O'Donnell, etc.). Fox News is never going to give that stuff away either nor would I expect CNN to. So keeping Hannity, etc. exclusive to the cable bundle will be a reason for some folks to stay there (although they're mainly older viewers; in 2017 the median viewer of both Fox News and MSNBC was 65, and 60 for CNN).