I'd say quite a number of people here would really enjoy Numberphile[1] and Computerphile[2] and I'd heartily recommend subscribing to and keeping up with them. I'm also heavily interested in tabletop and video gaming and I keep up to date with both of those through a combination of YouTube and podcast subscriptions.
LGR
TechMoan
8 Bit Guy
This Does Not Compute
Big Clive
AvE
The "default" content on YouTube is indeed low-quality crap like what you mention, but there is a lot of great content on there.
On YouTube, you can learn about any skill, the quality of "teachers" varies greatly, but there really are some exceptionally good ones out there.
I'd suggest you check out some of these channels
1. Adam Neely - a (bass) musician, he hosts Q/A videos very regularly, responding to comments in previous videos. The quality of his comments section is unlike anything I've ever seen before, real, in-depth questions, insights, recommendations etc... Exceptional channel in so many ways
2. 3blue1brown - a mathematician who focuses on helping viewers build an intuition for various dry mathematical concepts.
3. Yoshiki Oshima - this one is very niche, but I mention it because there are uncountably many high-quality niche channels. His channel basically archives old computer research videos, lots of stuff on Alan Kay, Ivan Sunderland, PARC, Douglas Engelbart, Seymour Papert and others.
Many many many many many channels with different focuses out there. YouTube has a lot more to offer than what the frontpage shows.
I mainly subscribe to woodworking and programming channels. It's generally something where I'm hoping to learn new skills and techniques, and for that, YouTube is incredible.
I also purchased my first home last year (100 years old) and channels like This Old House have been incredibly helpful with many maintenance tasks.
The evenings we have spare time, we fire up the PS3 or PS4 and play something. Much more engaging than TV :)
The kids use netflix etc though, but also a lot of youtube.
There is one thing I miss about youtube from the earlier days though. People uploading and creating stuff because they wanted to do it, not because they wanted to make money. It makes such a huge difference.
My main hobby is board games. An excellent way to see how a new game plays is by watching videos of other people playing it and giving reviews on it. The hobby isn't big enough that you'll see shows about this on mainstream TV, but pretty much anyone into modern board games I'd almost guarantee uses Youtube on a regular basis.
A few of the bigger channels just for board games include: The Dice Tower, Rahdo Runs Through, DriveThruReviews, Shut Up Sit Down, the BoardGameGeek, and Game Night. Incidentally I was just in Columbus, Ohio for one of the larger board game conventions (Origins) and spotted most of these people working or hanging out.
On cooking & food:
jastownsendandson - 18th century history and recipes
foodwishes - nice succinct no fuss recipes, focus on the recipes
TabiEats - casual/fast food reviews and stuff from Japan
gundog4314 - reviews of military rations
Global news and Culture:
PBS NewsHour - public news, nice balanced and thoughtful news without lots of histrionics
ARIRANG TV - korean state cultural TV, mostly because I have Korean family members, but some interesting shows from time to time also "ARIRANG NEWS" for regional news and local Korean politics and ARIRANG CULTURE for more specific Korean arts stuff
Great Big Story - hard to explain, but brilliant short videos from all over that make you feel better about the world after a hard day
Big Think - another hard to explain channel
TheJapanChannel - mostly interesting vignettes from Japan, I find them kind of soothing for some reason
Talk to me in Korean - supposed to be a language learning course, but interesting insights into Korean culture, sometimes some interesting walks around different parts of Korea, skip the language stuff and enjoy the rest
Abroad In Japan - an Englishman in Japan, very dry humor, endlessly entertaining
Korean Englishman - an Englishman in Korea, less dry humor, also endlessly entertaining
OsiyoTV - Cherokee Nation TV, well produced show on Cherokee topics
2hearts1seoul - nice fairly calm looks at stuff in Korea
NHKWorld - Japanese national shows
Simon and Martina - two hyper hipsters in Asia, I like them, but they can be polarizing
TheKoreaSociety - serious talks on Korea and regional issues
Retrocomputing and gaming and stuff:
Kim Justice - some incredible histories of the UK computer gaming scene, fantastically produced all around, an actual hidden gem on youtube
TNT Amusements - business advertisement for a company that refurbs arcade games, fun crew and can be entertaining and informative from time to time
Pixelmusement - old games, my favorite show is "Shovelware Diggers"...strangely relaxing review of crapware dos and early windows games from a 1000 games CD.
Retro Core - English reviews of retro games from Japan. The guy who does it is kind of infectious and opinionated, but has a definite voice.
Computerphile - interesting old to new light computing topics
The Ben Heck Show - various electronics and retro gaming/computing topics, serious hardware hacking
Top Hat Gaming Man - reviews of various games and stuff, puts a bit of effort into production
Grand Illusions - weird toys and nick-nacks, infectious host
Techmoan - odd old things, just watch it
EEVblog - intense teardowns of everything
Game Sack - great, well produced retro gaming
Metaljesusrocks - another great, well produced retro gaming show
Matt Barton - his show "Matt Chat" has interviews with some absolute gaming legends, amazing stuff
Jeremy Parish - one of the "old men" of gaming journalism, has lots of on-line presence, but does tons of interesting reviews
Cars:
Motor Trend Channel - you know what this is about
fullychargedshow - electric cars
Music:
NewRetroWave
Generic Male DJs
A Tribe Called Red
WinhamhillLovers
Movies:
RedLetterMedia - sarcasm at its finest
Nerdwriter1 - great analysis of films
I, 31 and a computer scientist working as a software dev, on the other hand, hate almost everything that's not in text form.
Because of vast amount of content on youtube, outside of the top channels in any specific topic, you might not even share any subscriptions with any of your friends.
As others have said, YouTube is huge with people around ten years younger than you and more.
Oh and Red VS Blue :-)
But I also go there for lectures. All sorts of conferences and talks and debates and lectures are up on youtube, it's just a matter of using the correct search terms. Most serious videos I watch are related to politics so then my challenge is in stepping outside of the mainstream people. No Noam Chomsky for example. When I want to challenge my views I might go to Bill Kristol's channel which is small but good or lookup some libertarian or alt-right stuff. Youtube is one of the greatest things about our current technological age, it just requires a bit of finesse to get past all the crap.
And video thumbnails are the most cringy thing you can see on the Internet. http://buyviewsreview.com/wp-content/uploads/2015/02/custom-...
It's sad to admit it but I avoid youtube whenever I can.
I get a weird culture shock whenever I ever see what it looks like to my kids though.
Among my friend group (mid-20s tech people in Seattle for the most part), YouTube is a non-entity. It never comes up in conversation. I personally never go to the front page of youtube to actually look at anything, I'm always searching for something specific. OTOH, we talk plenty about Netflix and podcasts.