Okay, I'm having trouble not saying anything mean here, so let's just stick to basketball logic.
Obviously another team would've done this. There was more available cap room this year than at any other time in NBA history. It would have happened.
BUT for argument's sake, let's presume it didn't and because the Celtics didn't help LeBron was forced to stay in Miami...okay, we'll there's still a super team that's reached the finals in 4 straight years there. Between them, a super nucleus of talent in Indiana, a potentially healthy Derrick Rose in Chicago coming back, and a Phil Jackson built team with Carmelo being relevant in the next two or three years, you're STILL not getting a crack at the finals for "5-7 years."
So now that the miami team is essentially dismantled, that basically just moves one good team from Miami to Cleveland. You've traded one for the other. Who cares that we helped Cleveland?! We KNEW the Heat could win. Right now, we don't know about Cleveland. Wiggins could be a bust for all we know. Kyrie could succumb to the injuries that have plagued him. This is a good thing initially, and even better because we get a nice piece in Zeller, another first round pick that who knows if it'll be something really valuable (probably not but maybe a serviceable all star!) or could help trade for something valuable.
It's like trading a player to get something for then before they walk away and you get nothing and screwed. We got something out of a superstar moving, and it's not even our superstar. How is this POSSIBLY a bad thing? Sorry but I don't even remotely agree with the OP.