WordPress Page Builder vs Theme: What Is the Difference?
A theme defines the site's presentation and template framework. A page builder provides an interface for composing layouts. Modern site-building products blur the boundary because many builders can also design theme-level parts.
Traditional split
Historically the theme handled templates while the editor handled content.
Modern overlap
Theme builders can control headers, footers, archives and content templates visually.
Integrated products
Divi and Bricks combine theme and builder concepts more tightly.
Choose for maintenance
The important question is who controls recurring templates and how easily the team can update them.
A practical way to decide
Use this page as a shortlist, then test the workflow against a real page you expect to maintain. Pay attention to editing speed, responsive behavior, reusable styles, licensing and how comfortable the future editor will be making routine changes.