One big takeaway from this, well two.
1) People now don't always know what channel games are on. At least casual viewer.
2) This is the big one. Pens/Caps are on TNT. Sometimes the local Root sports is also carrying the game and the TNT feed is blacked out. That doesn't help ratings.
And then of course the third, and most important takeaway. Many of the games that ESPN has shown on the "big network" this year have been played on Sunday nights. At exactly the same time as Sunday Night Football on NBC. And those games, predictably, got killed in the ratings.
If you take those Sunday night games out and only look at the rest of the games, ESPN's ratings would actually be up on the season.
On you point two, TNT had a Bruins game on that was blacked out in Boston. On the average, 661,000 people watch Bruins' games on NESN. More than watch the average game on TNT in that one market alone. How many hundreds of thousands of more people would have watched that game on TNT in the Boston market if the game wasn't available on NESN and only on TNT? And of course a similar thing has happened to them with Penguins games and Ranger games, to name two teams that have high local viewing numbers.