I am wondering if the Project Gutenberg and it's future merge into WP
Core will make all other PageBuilders obsolete. The Github FAQ states: "A lot of features are planned, too many to list. But a rough roadmap is: v1) post and page editor v2) page template editor, v3) site builder."

I actually like that idea as there are current dozens of competing page builders that all have different standards. Having one build into Core makes sense.