Marriage may be a weapon, but it’s just one weapon in a whole arsenal.
I agree with your thesis that ‘marriage is unnecessary’. Whether in a marriage or a de facto relationship, two parties must make a conscious effort if the relationship is to be successful. Legal binding has nothing to do with it.
But, as someone who lives in a country where de facto relationships and marriage have almost equal legal standing*, I’m sorry to say it is not going to fix a lot of the problems you list. Those problems are rooted in culture, and the culture that surrounds the subjugation of women isn’t going to change just because we abolish marriage.
I’m so sorry to be the bearer of this bad news, but we’ve got a much bigger problem.
Many of the points you raise are problems with a general acceptance of this strange and arbitrary but long-standing division of power between the sexes. (Thank the patriarchy.) Men do real work; women do housework. Men are intelligent; women are emotional. Men act; women talk. From a young age, boys and girls alike are taught these lessons, along with that magical ideal of a monogamous relationship that lasts until death, in which the man provides for the woman, and the woman provides for the man. And, even if you take away marriage, that ideal still exists, and those strange binaries still underpin the culture.
Take away marriage, and the complications of divorce remain; they just get applied to de facto relationships as well. That is, if you agree that separating from a partnership should result in a fair distribution of assets (taking into account the contributions to earnings, the contribution to homemaking and child rearing, the future earning potential of both parties, and any other relevant factors). If you don’t agree with that, then I’m not sure what it means to be a partner; you’re basically a house-mate with benefits.
Take away marriage, and domestic abuse (including intimate partner rape) doesn’t leave with it. Domestic abuse is live and kicking (now there’s an awful pun) in de facto relationships and non-cohabiting relationships and LGBTI relationships and none of it is because of marriage. When you elevate other relationships to be equal to marriage (good thing) then the shame and guilt of ending those relationships becomes equal to the shame and guilt of ending a marriage (bad thing). I know a lot of women who have lived through domestic abuse, and only a tiny proportion of them are married. (I am one of them.)
Take away marriage, and the legitimacy of children ceases to be of concern; but mothers will still be judged, and women’s reproductive rights will still be contended. Men and women alike have been conditioned by their upbringing to believe that certain conditions must be met before a pregnancy is appropriate. And this doesn’t even begin to touch upon the reproductive rights of LGBTI people.
Your other points I can’t really talk about. They’re not within the realm of my experience. Child marriage is not an issue in my experience of Australian culture (though I believe there are stories of this happening, I don’t believe it is a widespread occurrence); paedophilia certainly is, regardless. Women in Australia are recognised as human adults with legal rights to sign for their own passports, etc., and property does not automatically pass to men.
Without marriage, other weapons are used to subjugate women. And all these weapons are powered by our unquestioning perpetuation of cultural norms.
I long for a future where relationships are just relationships—they don’t need some qualifier slapped in front of them like same-sex or polyamorous or de facto. Relationships between consenting adults should be defined solely by the people within them and their agreed expectations of each other.
But I don’t think that can happen until we question our assumptions about what it means to be in a relationship and, more importantly, what it means to be a man or a woman.
*It’s not quite equal, but it’s a lot better than in most countries. For example, if a de facto couple (defined as cohabiting for six months or more) separates, the parties must sign a separation agreement, in which all assets are listed and apportioned. The two parties must receive legal advice from two independent solicitors—just as you would in a divorce. Going through an amicable separation is difficult because the solicitors will generally push you to fight for more, even when you’ve already agreed on the division of assets directly with your former spouse. However, one situation unique to marriage in Australia is that when you get married, your will becomes invalid (unless your will states it was made ‘in contemplation of marriage’)—in the case of your death, all your assets go to your spouse. That doesn’t happen with de facto relationships.