I don't see how GCN makes any money. Lots of little sponsor deals, sure, but they have so many employees to pay and a lot of their content is expensive to produce.
Some dad films two English speaking kids somewhere in Europe doing random things. They have 14M followers and often get 10M+ views. A 20-something girl does cute crafty things. 6M followers and every vid gets 2M views. She's branched out into merchandise now. Meanwhile, GCN has 2.5M followers (good) but only averages 100-150k views per segment.