I thing you don't need to delete footer file.
Just override footer file app/design/frontend/Vendor/ThemeName/Magento_Theme/layout/default.xml or in your luma theme with this content:
<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceContainer name="footer-container">
<block class="Magento\Theme\Block\Html\Footer" name="footer" template="html/footer.phtml"/>
</referenceContainer>
</body>
</page>
And call your static block in ../templates/html/footer.phtml file.
echo $this->getLayout()
->createBlock('Magento\Cms\Block\Block')
->setBlockId('your_block_identifier')
->toHtml();
Now your block content displayed in all pages
Also using this method you can do your other customization like calling newsletter, get default footer link and custom php codes as per your requirements.