Hi there,
The way those old child themes work is to set the Customizer defaults. If you have saved options, the child theme won’t look like the demo, as the defaults have been saved over.
If you delete your settings, your site will look like the demo, but you will lose your saved settings.
In most cases, I would suggest ditching the child theme and using the Customizer to achieve a similar look. It’s likely time we remove those themes from WordPress.org.
Let me know if that makes more sense or not 🙂