Wonder how much of his decision will come down to what happens to Wade. If Riley makes a good move and dumps Wade to get the Heat some help then Lebron would likely absolutely stay. If the Heat are looking to keep Wade and have him go into next season still as the starter he would have to think about it.
The Heat are not winning a title again with Wade as their starting SG. At this point in his career his body has just failed him. Pretty much his entire game was based on his quickness and ability to finish around the rim, and he has lost all of it now without ever fully developing an outside game he could fall back on.
Heat can't get rid of Wade's contract. The big 3 have early termination options which means they can become FA's if they want after this year.
If for some reason they all opt out and sign lower contracts then they can re-stock the roster but I'm sure Wade would need a good reason to walk away from 40 mil.
Otherwise I agree that Wade is done. He never developed his game so now that his athleticism is gone he's just looks lost out there.