Will Block based themes still have posts AND pages?

Hi:
Just trying to get oriented to the way themes are going to work in Gutenberg – when themes stop being based on php templates, will there still be posts and pages? If so, will there need to be a page.html template (corresponding to the current page.php) or will all pages in the site use the same template?

Responses as well as helpful links on this appreciated.

Thanks!

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