Even PewDiePie, the biggest YouTuber of all with close to 55 million subscribers only got $32 and $38 in ad revenue on his last two videos according to a video he uploaded today, titled SHE WANTS MY YOUTUBE MONEY! Pure gaming channels (which PewDiePie is not) seem to be still going strong, some even seeing more ad revenue than before the adpocalypse. So it really depends on the content people create and if they create the wrong content, with *gasp* edgy humor, the most dangerous of weapons ever created by man apparently, even millions of subscribers means you don't get anything and have to make money through donations or promo deals.
But I completely agree with your other points :)
Absolutely! And that's a good point to bring up. This reminds me of my first startup, macmod.com, a community site for people that modified their macintosh computers. It was very popular. We had multiple links on apple.com, even on their Mac Mini product pages.
Alas, nerds don't click ads, they don't buy products with markup, and they're an absolutely horrible target market with respect to general marketing and revenue channels.
So, I certainly agree with you there. If I'm an advertiser, I'm unlikely to want my ads showing next to PewDiePie, unless maybe I'm selling a Squatty Potty.