A <script> tag will block DOM tree construction and rendering in browsers but will not block scanning ahead for things to load (and at least in Firefox won't even block tokenization of the HTML). So if you have a <link rel="stylesheet"> at the end of <body> it will likely start loading even before the scripts before it have had a chance to load and run.
A bigger problem is that in some browsers (not Firefox, but iirc yes Chrome) that stylesheet load will then itself block rendering.
A bigger problem is that in some browsers (not Firefox, but iirc yes Chrome) that stylesheet load will then itself block rendering.