Left ESPN for the NFL Network years ago simply because of a lack of interest in all of the other sports they were promoting. If you want college football, you turn to the Conference of your choice channel. If you like high school football, you turn to a local channel. ESPN just became irrelevant. Too many sports specialty channels that give a viewer exactly what they want, when they want it. Maybe it was a lack of time to follow every sport, or fantasy football moving to the Internet, or just one too many bowling classics that influenced the switch, or maybe a combination of things. ESPN just became as old as Ron Jaworski, Mel Kiper, Jr., Chris Mortensen, Jeff Van Gundy, Chris Berman, Michael Wilbon, Brent Musburger, Sal Paolantonio, etc.
One thing ESPN can still hang their hat on is their radio broadcasts. Not because they are so much better, but because ESPN still dominates sports radio, (at least where I am). Any car ride turns into the perfect time to tune in ESPN radio, during football season. Mike and Mike in the mornings for example is awesome, again during football season. Maybe this will be taken away from ESPN someday, but for now, its still a useful seasonal product that they offer and that I still enjoy.
Another issue with ESPN is that they do not have a league or a conference throwing money at them. The NFL has so much money, that they can pay any Hall of Famer they want to host or guest on any show they want. People like to see their favorite players speaking of the sport they love....and what current or potential Hall of Famer does not want to be on the network devoted specifically to their sport? Nice retirement job.
ESPN probably can't succeed being a jack of all trades when it comes to sports. There are just so many other specialty sports channels that are going to throw 24 hours of programming into a sport, where ESPN can only throw a couple hours as it spreads its coverage of sports in general all around. Talking about golf will promote channel changes instantly.
Finally, there is the shrinking of TV/cable viewers overall as the Internet is the millennial viewing option of choice. As the previous author stated, its kind of going the way of the newspaper over the last 15 years.