<p>I’m not sure the institution of marriage has declined as much as we believe, meaning we look at a relatively short period and extrapolate as though that is normal. If you go back in time, both in the US and in other countries where records exist, marriage with a religious or civil ceremony is rarer. People lived together. They established “common law” marriages. If you read Jane Austen, you know people would cross into Scotland and proclaim themselves married.</p>
<p>I’ve read histories that looked at English county records which find relatively few actual marriage ceremonies, with those mostly involving 2nd marriages and wealthier people where property and inheritance was an issue. </p>
<p>I’m not sure about the statistics any more - and I don’t trust the numbers anyway - but my guess is marriage had a heyday lasting substantially less than 100 years. In a humorous vein, remember Eliza Doolittle’s father Alfie gets married after he comes into money (as a moral philosopher!). So he marries Eliza’s mother.</p>
<p>One can argue marriage as we think of it became more popular as we became wealthier but that definition was never fixed as we want to believe.</p>