How do I use esc() in html form input AND get readable text?

Problem:
This code

PHP Code:

<?php $sample_text = 'The quick brown fox!';
<?= form_input ([
 'name' => 'sample_text',
 'id' => 'sample_text',
 'class' => 'form-control input-sm',
 'value' => esc($sample_text, 'attr')
]) ?>

Yields a textbox with the value "The quick brown fox!"

How can I escape output but still produce readable text in the form? I want "The quick brown fox!" and simple sentences to be plaintext but everything else to be escaped.
Is 'attr' the correct context to use here?