There are two assumptions you make that can make your point(s)...meaningless.
Don't assume that the 'promise' means anything to me, and your assumption that the only thing that means anything from a 'historical perspective' is 'titles' ...is at best a moot point for about 40 years....after we've all forgotten his childish egocentric display..."The Decision"...and his dog and pony show.
Seriously, Is there anyone who wouldn't think that LBJ was a great player? At worst, historically, he ends up known as the best NBA player to never win a title. Meanwhile, the guy is worth at least a half a billion dollars, and beloved by his fans, not only in Cleveland but around the world. Wow...and that's the worst even if Northeast Ohio and his hometown don't mean a damn thing to him.(which is NOT the case).
Instead, he pulls a dick move that makes him come off as a jerk on a national stage...all to chase titles. He had a unique opportunity in Cleveland to distinguish himself from the rest of the pack. Moreover, he had it good in Cleveland...real good. That is a point of Rosenberg's article.
Instead, he sold out himself, his reputation and goodwill from fans. He came off as narcissistic, stuck it to his fans who wore their hearts on their sleeve for him, left his former team in the lurch and without viable options, and didn't give the owner the courtesy of a heads up of his decision. .....Extremely immature, lacking class, and a sucker punch to those who cheered hardest for him.
Lebron's biggest mistake?....making his 'friends' his advisors. Tough to go against their advice...tough to fire them, even when that is what should be done. That's how I'll know that Lebron has really matured...when he fires Maverick Carter.