As I have had the opportunity to discuss this with another participant, I think it would be worth considering the inclusion of a basic theme and a theme built with multiple page builders in mind.
The idea stems from a free theme already available on WordPress.org Repository ( https://wordpress.org/themes/page-builder-framework/ ). While I understand there is resistance to builders due to the Gutenberg issue, page builders are a very active part of the WordPress ecosystem.
I personally think that including a theme that is built for use with multiple free and paid page builders would be a valuable asset in helping people begin building their site(s).
This doesn't involve making any changes to core. It isn't something that is automatically activated. It's just a useful tool I think would be nice to see included in the installation package.