If you ask LeBron James, his reasoning behind changing his number from 23 to 6 is to pay tribute to his idol Michael Jordan. The business side of a change also can't be ignored. His #6 jersey sales would be through the roof, especially if he changes teams. His basketball cards will also be impacted.
Collectors pay premiums for cards that are serial numbered to LeBron's present jersey number, 23. If the switch to number 6 goes down, it suddenly opens up the market for those cards to catch an unexpected bounce.