displaying the loop with or without WP_query

How come I can’t display the loop of posts on a page with

<?php if (have_posts()) : ?>
   <?php while (have_posts()) : ?>
      <?php the_post(); ?>

         <?php the_content(); ?>

   <?php endwhile; ?>
<?php endif; ?>

but I can with a WP_query?

$the_query = new WP_Query( array('post_type'=>'post', 'post_status'=>'publish', 'posts_per_page'=>5) ); ?>

<?php if ( $the_query->have_posts() ) : ?>
<?php while ( $the_query->have_posts() ) : $the_query->the_post(); ?>

<?php the_content(); ?>

<?php endwhile; ?>
<?php wp_reset_postdata(); // reset the query  ?>
<?php endif; ?>