Yes..but are you saying the entire EC of the NFL has been weak over their entire run? I know the Bills, Jets, and Dolphins have been weak, but I'm talking about the playoffs.. and you don't get a bye in the NBA like the NFL.. you have to play three series before the finals.. I see what you're trying to say, but the two aren't exactly comparable. The Pats have had to play some very tough teams in the two-three games they've had to play in the playoffs. (Of course a seven game series is also entirely different).
2018 - Kyrie hurt
2017 - IT finds out his sister died right before the playoffs start, and doesn't play most of the ECF because of an injury (lost to GS 4-1)
2016 - Detroit (4-0), Atlanta (4-0), Toronto (4-2) (beat Golden State 4-3, Green suspended one game)
2015 - Boston (4-0), Chicago (4-2), Atlanta (4-0) (lost to GS 4-2)
2014 - Charlotte (4-0), Brooklyn(4-1), Indiana(4-2) (lost to San Antonio 4-1)
2013 - Milwaukee(4-0), Chicago(4-1), Indiana(4-3), (beat SA 4-3)
2012 - New York (4-1), Indiana (4-2), Boston (4-3) (beat OKC 4-1) This is the year Miami won game 1 at home and then won game 2 with Rondo scoring 44 points... Miami shot 47 free throws and the Celts still took it to OT. Celts won the next three games.. and LeBron had his great game 6.
2011 - Philadelphia (4-1), Boston (4-1), Chicago (4-1), (lost to Dallas 4-2) Rajon Rondo is injured by Wade and plays with a dislocated elbow.
For most of those years the two - four other top teams have been in the WC. Teams like GS, OKC, San Antonio, LA Clippers (at times), Houston... all of these teams have had to play each other before the finals. Cleveland and Miami have had very weak opponents on most of their runs..nothing close to what WC teams have had to go through..and in a few cases they've had to play the other team without key players.
Yes, LeBron has also factored into this of course as one of the most dominant players of all time, but when he's gotten to the finals and had to play just one WC team he's failed more often than not... I'd like to see what his run would have looked like if he'd been in the WC all these years. Partially just for interest but also because I'm admittedly a Celts homer and I'm sick of watching him beat the Celtics. So yes I know I'm diminishing his impact I know, but also I don't think you can look at the EC over the last ten years and tell me there have been even two really strong opponents to the Heat and Cavs. Hawks and Raptors have been flawed teams the entire time.. closest thing they've had to a rival really is Boston early and Indiana over the past few years. I count the last two Boston trips as weak teams as well since the major injuries.. even with that Cavs needed Kyrie to carry the team a lot in the ECF last year and the C's took him to game 7 this year without two of their best players and two crucial role players (especially with those first two out, Larkin is very much a role player, but he would've been a huge help this finals simply to take some of the ball handling pressure off of Rozier and not require Smart to dribble up as much.)