Thats not true. You had one .php file (or more, if you use includes) where everything was located: the HTML, if necessary any JS via <script> and interspersed with <?php … ?> depending on what dynamic stuff you wanted to output.
And this is parsed to one output file that is sent back to the browser.
OK, now you can do it using just one JS framework i guess? But is it a revolution? A breakthrough?