You're missing half of the profit equation - COST!
NBC does really well off the NHL because the rights are so cheap, only $200mm annually.
ESPN is paying 2.35 times that just for the Playoff and NY6 - that's 9 games! ($435mm)
Let's say hypothetically, all 9 games drew that 13.8 (they didn't), that's 124.2 total ratings points. Do the math, that's $3.5mm per point! (Again, a low end estimate, as all the games didn't draw close to the Title game).
At that rate, all NBC would need from their 112 game slate is 57.14 points to match the investment. The Final averaged a 3.0, so there's 21 already. Clearly, NBC is getting a better deal.