...And that's on LeBron. He wanted to replicate what he had in Miami. As de facto GM, he chose a co-star who could slash and score (Wade:Irving); a stretch 4 who could shoot/rebound/defend (Bosh:Love); a rim-protecting rebounder-enforcer (Haslem/Bird:Thompson); and a 3 and D guard (Chalmers/Allen: Shumpert/Smith). He thought he was building a younger replica of what he had in Miami. He undervalued what he had in Miami.
Irving is no Wade. He's not a leader. He never developed the rapport that Wade and James established over years. And most importantly he's not a shade of the defender Wade is. Love can shoot better than Bosh, but he is an atrocious defender, whereas Bosh defends from the rim to the arc exceedingly well and can score when called upon. Similarly, Shumpert and Smith don't hold a candle to Chalmers and Allen, respectively.
On top of it all he's not same player. Still amazing, but he's lost his jumper and has played a ton of basketball - 6 straight finals appearances with an Olympic Gold thrown in for good measure.
He built a good team, no doubt. Just not a championship team, and they're being exposed by a much deeper and more talented team (Thunder, Spurs probably would have yielded similar results, too).