You are correct, but why is this a problem in the case mentioned by the author?

    $ cat > hello-world.lisp
    (defun main () (format t "Hello, World!~%"))
    $ sbcl 
    * (load "hello-world.lisp")
    T
    * (save-lisp-and-die "hello-world" :toplevel #'main :executable t)
    [undoing binding stack and other enclosing state... done]
    [defragmenting immobile space... 1110+19908+28500+22601 objects... done]
    [saving current Lisp image into hello-world:
    writing 4816 bytes from the read-only space at 0x20000000
    writing 2320 bytes from the static space at 0x20100000
    writing 2383872 bytes from the immobile space at 0x20300000
    writing 15190112 bytes from the immobile space at 0x21b00000
    writing 39911424 bytes from the dynamic space at 0x1000000000
    done]
    $ ./hello-world 
    Hello, World!
    $ ls -lh hello-world
    -rwxr-xr-x 1 user user 56M Aug 23 10:23 hello-world