They want whatever is IN. Whatever is BIG. Whatever is the most POPULAR.
It's all about "big names" swirling around the community. "Have you heard of X?" Because "discovering X" and getting a big deal makes you famous.
"Driving profits up 3% over last quarter" is not what a hot shot maverick does. It's not cool.
So finding tens/hundreds/thousands of smaller (but successful!) channels isn't popular. Humans can't process that easily. And when it comes to impressing your boss in that industry, you want bite-size chunks. You want the next Macklemore, not 30 amazing electrical-engineering channels.