I'd contend that the coasting (by the team, not just LeBron) very well could have been what cost us a better shot in the 2017 Finals.
The 2016/2017 Cavs went into that series with little to no track record of being able to lock down defensively for 48 minutes, generate offense with James on the bench or limit turnovers. And lo and behold, all 3 items reared an ugly head in the finals, where the Cavs were facing a Warriors team that you simply have to play perfect against to hope to beat.
Yes, Warriors are a Kyrie Irving knee cap away from possibly only having 1 title in 3 years, but the Cavs are a Curry decision or two away from basically being the Buffalo Bills of Basketball.
I totally get that Lebron can coast and turn it on at a moments notice and amp up his performance to historic levels. The problem this year was that the rest of the Cavs couldn't really do that. Season prior saw JR Smith busting it defensively in every game regardless of if his shot was on or not. TT doing his best Rodman impersonation, Shumpert's active hands making a difference v just getting called for reaching.. Cavs needed to win the details this year, but had no practice doing so.
Very "Rocky v Clubber Lang I" if you ask me.