This is a great solution, thanks! 
My ready.php hook: 
$wire->addHookAfter('Fieldtype::markupValue', function($event) {
  $page = $event->arguments(0);
  $field = $event->arguments(1);
  if($field->type == 'FieldtypeTextareaLanguage' or $field->type == 'FieldtypeTextarea') {
    $displayValue = strip_tags($page->get($field));
    if(strlen($displayValue) > 100) {
        $displayValue = substr($displayValue,0,97).'...';
    }  
  }
  else {
      $displayValue = $page->get($field);
  }
  
  $event->return = $displayValue;
});
 
Only problem I am seeing now: after the modal window to edit the pageTable fragment closes, the content refreshes and shows the full content again. The URL that requests the new content is this one: 
/processwire/page/edit/?id=1293&InputfieldPageTableField=content_elements&InputfieldPageTableAdd=1294&InputfieldPageTableSort=1294,1295,1296,1297,1298,129
Any idea how I can hook into the refresh? I will try the runtime property option too, just in case.