You are horrifically overvaluing George.
No he's not. Superstars don't grow on trees, ones that just signed 5-year extensions rarely ever (never?) get traded and wings are a very valuable commodity in the NBA as of late. Check out the contracts of Gordon Hayward or Chandler Parsons. Actually I just made a quick chart of the top 100 player salaries and the distribution looks like this:
PG 23%
SG 18%
SF 15%
PF 25%
C 19%
That might seem like wings don't get paid but what it really indicates is that it's the thinnest positions in the NBA talent-wise. If there were more star wings they would be paid. The NBA is full of money to pay productive players. To illustrate this point I took the top 20 salaries and compared the NBA position of those salaries against the top 100. The results are:
17% of the top-20 highest paid players are PGs
11% of the top-20 highest paid players are SGs
33% of the top-20 highest paid players are SFs
24% of the top-20 highest paid players are PFs
16% of the top-20 highest paid players are Cs
Good-to-great SFs in the NBA are paid like crazy because they are unicorns. Where the other positions have a relatively consistent distribution throughout the top 20 and top 100 salaries respectively, SFs have a much higher occurrence of being paid contracts that fall in the top 20 than any other position. Much higher.
George is valuable for so many reasons: elite defense, youth, scoring, size, length, long term contract. His position as a SF is certainly another.