@WashedOutGundamPilot @Niloy005 I would argue that it is because of their assumption that it will just happen that they take it for granted. If they realized much sooner (in their 20s) that they could very well be sabotaging their chances by squandering their time and not seeking a husband as soon as possible, they might not be so absent minded about it.
In a way, the lack of prioritization shows that they do not want a family as badly as they claim. They would not delay things if they did.
But man, you know, we all want challenges, and if getting a boy to like you is essentially an unconscious process for you, why would you be invested, and if getting a girl to love you is a monumental task, then they're just gonna be more invested.