That’s a theory, but you’d need some data to support it and there are some potential confounds. For example, if someone decides children are out of the question

That’s a theory, but you’d need some data to support it and there are some potential confounds. For example, if someone decides children are out of the question because they can’t afford significant costs and instead decides to travel at considerably lower cost, that doesn’t tell us what choice they have made in an alternate scenario where policies made the financial burden much lower.