Strictly speaking, the question is asking why women can't get pregnant without the menstrual cycle. As you mention in your post, the period occurs at the end of the cycle, therefore without a cycle, pregnancy will not happen.
No. Menstruation occurs if there's no implanted and viable fetus by ~24 days after ovulation. A few days later, ovulation occurs, and the cycle repeats.
What are you saying no to?
Maybe I read it wrong. Pregnancy and menstruation are alternate endings for the cycle. So, as GP said, a woman could theoretically get pregnant on her first cycle, without menstruating.
I think you are agreeing with the comment you responded to.
Maybe so. Too late to delete.
Can you provide a car or software development analogy?