diff --git src/wp-includes/default-filters.php src/wp-includes/default-filters.php
index e9ca31f5f7..93a25bf8e1 100644
--- src/wp-includes/default-filters.php
+++ src/wp-includes/default-filters.php
@@ -557,7 +557,6 @@ add_action( 'wp_default_scripts', 'wp_default_packages' );
 
 add_action( 'wp_enqueue_scripts', 'wp_localize_jquery_ui_datepicker', 1000 );
 add_action( 'wp_enqueue_scripts', 'wp_common_block_scripts_and_styles' );
-add_action( 'wp_enqueue_scripts', 'wp_enqueue_classic_theme_styles' );
 add_action( 'admin_enqueue_scripts', 'wp_localize_jquery_ui_datepicker', 1000 );
 add_action( 'admin_enqueue_scripts', 'wp_common_block_scripts_and_styles' );
 add_action( 'enqueue_block_assets', 'wp_enqueue_registered_block_scripts_and_styles' );
diff --git src/wp-includes/script-loader.php src/wp-includes/script-loader.php
index fd1bf4b6fa..53b083c790 100644
--- src/wp-includes/script-loader.php
+++ src/wp-includes/script-loader.php
@@ -3657,21 +3657,6 @@ function _wp_theme_json_webfonts_handler() {
 	add_action( 'admin_init', $fn_generate_and_enqueue_editor_styles );
 }
 
-/**
- * Loads classic theme styles on classic themes in the frontend.
- *
- * This is needed for backwards compatibility for button blocks specifically.
- *
- * @since 6.1.0
- */
-function wp_enqueue_classic_theme_styles() {
-	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
-		$suffix = wp_scripts_get_suffix();
-		wp_register_style( 'classic-theme-styles', '/' . WPINC . "/css/classic-themes$suffix.css", array(), true );
-		wp_enqueue_style( 'classic-theme-styles' );
-	}
-}
-
 /**
  * Loads classic theme styles on classic themes in the editor.
  *
@@ -3683,6 +3668,7 @@ function wp_enqueue_classic_theme_styles() {
  * @return array A filtered array of editor settings.
  */
 function wp_add_editor_classic_theme_styles( $editor_settings ) {
+	return $editor_settings;
 	if ( WP_Theme_JSON_Resolver::theme_has_support() ) {
 		return $editor_settings;
 	}