“Every eleven minutes” because each “half hour” episode is two separate segments totaling 22 minutes.
Broadcast was utterly unbearable when I visited the US 20 years back, I can't imagine watching it today.
https://www.dictionary.com/e/pop-culture/the-wadsworth-const...
And we can ignore creators who over-monetize if we want (or buy Premium or use adblocking).
I heard about this a few months ago, and have since checked when the actual content starts in the videos I watch. I certainly can't agree with 30%, usually in 15-minute videos, the introduction is 1-2 minutes before they go into the meat. The bigger problem is all the filler, sponsorship breaks, "remember to ring the bell" etc., that occur at seemingly random points, though I don't think it adds up to 30% filler even if you count all that. Maybe I just skip over most of the garbage.
That's "non-useful" content rather than "non-content", those 30% are intro and filler which you might also find in non-youtube content. And obviously it also depends strongly on what kind of content you're using youtube for. Skipping the first 30% of a recital is probably going to skip interesting content.