I'm still not really following the point about one output file? That might be Make's stated purpose, but a Makefile rule can certainly create extra files as a side effect (or do pretty much anything a shell user could do, from creating directories and downloading files to launching applications)

One of my projects has a single makefile rule which downloads and unzips a tarball, applies a patch to it, then builds the application within, resulting in half a dozen binaries which are then used in building the rest of the project.

Edit: Ah - I see what you mean now, in your subsequent comment.

Yes, but this is not particularly relevant to the user. With pattern rules it's trivial to define a large number of targets automatically, such as in the example (from the manual):

    objects = foo.o bar.o

    all: $(objects)

    $(objects): %.o: %.c
            $(CC) -c $(CFLAGS) $< -o $@

The problem is a target with more than one output files, that target would look something like, which does work

    foo bar: baz
         compile $< -o foo -o bar

    foo: baz
         compile $< -o foo -o bar

    bar: baz
         compile $< -o foo -o bar

Scroll down to "Grouped targets". I think these address the concern you raise.

The snippet you have shown is an example of the "independent targets" pattern which the first half of that page also covers.

  foo: baz
    compile $< -o foo -o bar

  bar: foo

(from https://news.ycombinator.com/formatdoc)

  A_MESS_OF_FILES := foo bar zot

  MAIN_FILE := foo
  SUBORDINATE_FILES := bar zot

  foo: baz
    sudo make me a foo

  $(SUBORDINATE_FILES): %: foo