I upvoted you, but I do disagree. Overall I see your points as explanations for/additional evidence of a more general gender gap — not as reasons to think it's a statistical illusion.
One point you didn't make, though it is hinted at by your first point, is that if the proportion of women in the field is increasing over time, women's average age will be lower than men's (assuming people tend to enter the field from college and not from other fields, which seems reasonable), which would distort the salary numbers in a genuinely misleading way.
One point you didn't make, though it is hinted at by your first point, is that if the proportion of women in the field is increasing over time, women's average age will be lower than men's (assuming people tend to enter the field from college and not from other fields, which seems reasonable), which would distort the salary numbers in a genuinely misleading way.