Are you sure? When I used to watch Battlebots on Discovery channel it was basically 6 minutes of action wrapped in 10 minutes of fluff and 15 minutes of ads. Discovery Magazine had 3 sections per half-hour; comparatively speaking any science channel in YT will have way more content, and a lot of it really good for specialized audiences. Travel YT are way more up-to-date and useful than TV travel documentaries used to be.

There's a ton of really good Youtube channels, and the level of information density is astounding.

I never said all content on TV was good. Similarly, not all content on Youtube is bad. But the most hyped/advertised content on TV tends to be pretty entertaining (and usually fairly accurately advertised), while the most hyped/advertised content on Youtube (i.e. frontpage) is 90% clickbait and 10% people I'm subscribed to.