NESN's got the potential to create amazing programming. There's years and years of NESN coverage of the Bruins and Patriots. NESN's covered the Bruins since 1983, and the Sox since 1984. That's 67 seasons worth of old material. Now, I'm sure there are rules/standards about showing old games - they don't want to step on toes. Just how NBC doesn't actively counter-program NFL games on Sunday afternoon. And they won't have every game readily available in their library - particularly the playoffs.
Heck, I'd bet dollars to donuts the league doesn't allow them to show old games. In the winter, if you're not watching the Bruins on NESN, the NHL wants you to watch whatever game's on NHLN or NBCSN or Center Ice...not relive the past Bruins games.
I agree, though, that it seems so easy to create good ideas for programming. I mean, you could easily Buzzfeed the network and make tons of "10 greatest/worst X" type programming. The 10 best Sox pitchers. The 10 greatest Bruins games. The 10 best outfielders of the 80s. The 10 most controversial Bruins calls (all of which happened post-2014, of course).
I mean, I'm not sure I'd watch it. I don't do sports radio, and I only watch the actual games on NESN. But I can't help but think that the audience for those ideas would more closely align with the average NESN viewer than "Fishing with Idiots", "Eating with Idiots", "Idiots Drinking Alot", and "Idiots Driving Cars".