Pretty much every one of these deals turned into a financial disaster. The biggest of these was probably Mariah Carey, who ended up being paid $28m not to sing [1].
My point is that the presence of massive deals doesn't guarantee continued growth or success.
The most ominous part of this article is the loss of 7m subscribers. ESPN has managed to shake off--so far--the overall trend that cable TV is dying. The average age of TV viewers is increasing [2], which is bad for advertising and thus bad for revenue.
In the US, the more subscribers a cable or satellite TV company has, the more bargaining power they have, which translates to lower per-subscriber content costs. This is why Comcast wanted to merge with TWC. It's all about reducing TV costs. It's also why cable companies will practically give away TV (ie your cable Internet is under $20 with a TV package or $60+ without).
So for the last 10+ years, ESPN has managed to thrive in a market where demographic trends are ultimately against them. The flood waters are still rising and eventually you run out of dry land.
[1]: http://www.nytimes.com/2002/01/24/us/record-label-pays-dearl...
[2]: https://www.washingtonpost.com/news/business/wp/2014/09/05/t...