Drupal 8 - Allow login by email

allow_email_login.php

<?php
/**
 * Implements hook_form_alter().
 */
function MODULE_form_user_login_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state) {
    // Allow login with email.
    array_unshift($form['#validate'], 'MODULE_user_login_form_validate');
    
    // Change the field label.
    $form['name']['#title'] = new \Drupal\Core\StringTranslation\TranslatableMarkup('Email or Username');
}

/**
 * Callback to check for a valid email for login.
 */
function MODULE_user_login_form_validate(array &$form, \Drupal\Core\Form\FormStateInterface $form_state) {
    if (!$form_state->isValueEmpty('name') && \Drupal::service('email.validator')->isValid($form_state->getValue('name'))) {
        // Try to find a user name for this email.
        if ($user = user_load_by_mail($form_state->getValue('name'))) {
            $form_state->setValue('name', $user->getUsername());
        }
    }
}

Could this code be integrated into the Drupal core? Or why doesn't Drupal implement login via email?