What does the last line of Piercy's "Barbie Doll" mean: "to every woman a happy ending"?

Marge Piercy's poem "Barbie Doll" is an ironic commentary on the value society places on outward beauty and perfection as well as the potentially deadly consequences of this emphasis.  It all starts, of course, with the title.  The Barbie doll has long been the iconic picture of what a woman should be.  In reality, she is outrageously proportioned; however, the term "Barbie doll" has come to represent the outward perfection of a female.

In this poem, the first stanza introduces us to a young girl, "normal" in every way:

This girlchild was born as usual
and presented dolls that did pee-pee
and miniature GE stoves and irons
and wee lipsticks the color of cherry candy.

Then, a careless but hurtful comment is made in her teenage years, one which will have a drastic impact, however unintended.

You have a great big nose and fat legs.

 
No matter how talented or able she is in any of the ways that count, all this young girls sees or hears is that she has a huge nose and thunder thighs.  Then, one day,

...she cut off her nose and her legs
and offered them up.

 By the last stanza we see her all made up and wearing a frilly, feminine nightie.  As people come to pay tribute, they commented on how pretty she looked.  Now they say it to her, when it no longer matters.  Then come the last lines, including the one you asked about:

Consummation at last.
To every woman a happy ending.

This young girl's ending was anything but happy, and this ironic line highlights that fact.  It is a facetious (sarcastic) wish that all women's lives would go as well and end as happily as this "Barbie doll's."  In fact, it is a warning and reminder that what other people say need not define who you (boys and girls, men and women) are.  This Barbie doll was pretty and talented but bought into the lie of a cutting remark; the speaker of this poem warns us not to succumb to such pettiness. 

What is your commentary on the last line of the poem "Barbie Doll" - "To every woman a happy ending"?

Marge Piercy's poem "Barbie Doll" is a social commentary on the unreasonably high expectations for women as set by society. The poem makes it clear this standard is impossible to achieve--at least not while one is alive--and starts with something relatively careless at a young age. The first stanzas outline an average girl's life up to the point where someone makes a random but hurtful comment about the size of her nose and her weight. From then on, everything she thinks about herself is shaped by that perceived insult until she finally commits suicide because she succumbs to the pressures and can no longer cope. 

The last stanza is a little different in tone, for it is the author's commentary on her death, and it is riddled with satire.

In the casket displayed on satin she lay
with the undertaker's cosmetics painted on,
a turned-up putty nose,
dressed in a pink and white nightie.
Doesn't she look pretty? everyone said.
Consummation at last.
To every woman a happy ending.

The visual Piercy creates is eerily similar to a pink-clothed Barbie doll in her packaged box which one might pull off the shelf in any toy store. The comments of the funeral-goers (all of whom are undoubtedly showing much more interest in her now than when she was alive) may be accurate, but they are satiric, as well. She was undoubtedly prettier alive than dead, but they could not or did not tell her so. If they had, this young girl might still be alive. The "consummation" line is satiric, in that this girl has finally achieved her goal of looking pretty in others' eyes but is no longer alive to enjoy or appreciate the adulation.

The last line, then, is probably rather satiric as well and therefore open to some interpretation. There are no true "happy endings" in the poem, and Piercy is commenting on the fact that this is not an uncommon problem with women and society. The last line, if rewritten, might read something like this: To all women who listen to what society tells you, this is the only way you will ever make society happy.  It might also read like this: If being pretty by society standards is your goal, women, this is how to achieve it. Or perhaps you have another slant on this line. In any case, the satire is evident.