I don't know the figures you are looking at, but an average salary isn't the same as the median salary. It's like that old joke: "Bill Gates walks into a bar and makes everyone a millionaire, on average." One programmer getting a $500K salary and 10 getting $50K leaves a $90K average.
Now if you are just using the words average and median as substitutes and are seeing figures talking about $80K _median_ salaries, then the "location/experience" are likely to be the explanation, but if you really are hearing about average salaries, you have to factor in that, in systems with the characteristic imbalance of wages, something like 85% of programmers will get below-average salaries.
Now if you are just using the words average and median as substitutes and are seeing figures talking about $80K _median_ salaries, then the "location/experience" are likely to be the explanation, but if you really are hearing about average salaries, you have to factor in that, in systems with the characteristic imbalance of wages, something like 85% of programmers will get below-average salaries.