Take PHP with composer: it works quite fine, but still you need all the dependencies downloaded from somewhere on Internet. Just a PHP script and the PHP interpreter works, but this is not how 99.9% of the software is written.

The php world invented the phar format [1] to deal with the single file tool/app distribution issue.

In fact, composer uses dependencies managed by itself in their sources. Then it gets packaged and distributed as a single file that includes all dependencies (composer.phar). That single file can be run by php as if it was any regular php file (including executing it directly and letting your system detect the required interpreter through the shebang).

https://www.php.net/manual/en/intro.phar.php

Self quote: this is not how most apps are written.

Funny how feelings change. https://xkcd.com/353/