Extremely American way of looking at it. Here in France most of my friends have been in committed relationships and living together for years, some have children, only one couple is married. Marriage is an holdover from a time far removed which is both utterly useless and slightly paternalistic.
I’m not American, thank you. Also, there were almost a quarter of a million marriages in France in 2022.
I think your view is an extremely Western way of looking at it. Maybe examine attitudes in India for example. Also Indonesia and many others; possibly a supermajority of people in the world, even.
In my experience the legal nature of it is not what encourages one to get outside of oneself, as the original reply describes.
In some European countries you can have that contract without marriage as such.