You're looking at it in the wrong way.
Currently people view linear TV on their TVs. Over an aerial service, a cable or satellite service.
Non-linear is starting to become a major part of TV viewing too - over satellite, cable or broadband (catch-up, on-demand, etc...)... These services are primarily meant for TV but can be watched second-screen on tablets and laptops/PCs/consoles in many cases.
Then there's non-linear over online services like Netflix and Amazon Prime - originally watchable on PCs/laptops and then tablets, but now quite often on devices hooked up to TVs - cable/satellite boxes, smart TVs, smart TV boxes/devices, consoles, etc....
YouTube has allowed the "rest of us" producers to create content. Instead of seeing more traditional platforms as coming to YT and taking over, we should see it as them seeing YT as a threat, as respecting the position that YT holds, of seeing it as a peer instead of an irrelevance - and by them coming to YT it means that there's a platform parity being created.
Instead of satellite service X being where everything ends up, or cable service Y... Everything's congregating on YoutTube. Again it's not PlayStation or Xbox... Or Apple TV... Or Kodi... Or Andrioid this or that... It's YouTube... That should be encouraging...
That's going to bring more eyeballs... And whilst it might be easier for people to view traditional programming, it also makes it easier for the new audience (for YT) that the traditional outlets bring with them to view more "YT" content.
Don't see it as a threat. See it as a maturing that can bring benefit to YT'ers.