Netflix did not corner anything. Cornering would involve owning such a large portion of a market that you can dictate your terms as a buyer or seller.

Netflix was the subject of cornering. Disney told Netflix to take a hike because Disney owns the most popular content. Netflix had to pay $500M+ for 5 years of Seinfeld to counteract the news that Comcast was removing The Office from Netflix.

Selling media is a low barrier to entry business. Selling media that has cultural cachet spanning decades is a high barrier to entry business, with the barrier being decades of time.