A site specific plugin that can be used to remove the Extensions & Services menu items from both the Admin and the Admin bar for all users apart from those with the manage_options capability (usually this would be Administrators)

ee-site-specific-plugin.php

<?php
/*
Plugin Name: Event Espresso site specific functions
Description: Add custom functions for Event Espresso to this plugin.
/* Begin Adding Functions Below This Line; Do not include an opening PHP tag as this sample code already includes one! */

//Remove the Extensions & Services menu for all but admins with manage_options cap
function tw_ee_remove_services_menu() {
	if( !current_user_can( 'manage_options' ) ) {
		remove_submenu_page( 'espresso_events', 'espresso_packages' );    
	}
}
add_action( 'admin_menu', 'tw_ee_remove_services_menu', 11 );

//Remove the Extensions & Services menu item from the Admin bar for all users bar admins with the manage_options cap
function ee_test_cap_current_user_can_context_filters( $cap, $id ) {
	if ( $cap == 'ee_read_ee' ) {
		if( !current_user_can( 'manage_options') ) {
			return 'you_no_access';
		}
	}
	return $cap;
}
add_filter( 'FHEE__EE_Capabilities__current_user_can__cap__ee_admin_bar_menu_espresso-toolbar-extensions-and-services', 'ee_test_cap_current_user_can_context_filters', 10, 2);

Ref: http://developer.eventespresso.com/docs/ee-capability-system-overview/

Forum: https://eventespresso.com/topic/hide-extensions-and-services/