> I can probably safely say that the decline of ESPN first started with the rise of well-produced TV shows on HBO, AMC, Netflix, etc.

You are remarkably wrong here. In fact, live sports has come to completely dominate TV over the last 20 years. 9 of the top 10 most watched TV shows in 2016 was a sporting event:

http://www.nielsen.com/us/en/insights/news/2016/tops-of-2016...

I would argue the opposite: that "prestige" TV shows are a response to live sports by networks that don't have NFL or NBA rights.