Both. Descriptively, the practical difficulty of changing the law isn’t the reason the law hasn’t been changed in this way; the reason is that a great many people would oppose it on religious, moral, and other normative grounds. Many other laws have been changed over time despite the changes being nontrivial to implement, because the necessary people agreed in those cases that changing the laws was for the best.
Both. Descriptively, the practical difficulty of changing the law isn’t the reason the law hasn’t been changed in this way; the reason is that a great many people would oppose it on religious, moral, and other normative grounds. Many other laws have been changed over time despite the changes being nontrivial to implement, because the necessary people agreed in those cases that changing the laws was for the best.