It may be a guard's league but players with guard-like skills are also getting bigger and bigger. For every undersized 2 guard who dominates the ball like a point guard, there's a SF or PF who is 6'8'' or 6'9'' and shoots the ball well and has a good handle.
That just makes dominant post scorers rarer and more valuable, because you still can't have a great team without somebody who can balance your offense with looks in the post.