No, you can use any program to launch executable scripts that start with #!. The kernel sees that magic number at the beginning of the file, tries to read a pro

No, you can use any program to launch executable scripts that start with #!. The kernel sees that magic number at the beginning of the file, tries to read a program path and arguments, adds the script as the last arg and executes the whole thing. The various shells are just a subset of the possible programs used.