“Fear of missing out” is used to explain why people use social media items they don’t need nor want. But marriage is an example too.
I know there is wholesome cases where people want to start a family with other people they like to spend time with.
But a lot of the times it was also “Hey I am of the age my siblings and friends got married. I should meet people with the sole goal of marrying them and raising children.”
(a) depends on the country and (b) is always slower and more complicated than when married.
Say your partner gets hospitalized and isn’t concious. As a married person you have the same last name and done. As an unmarried person like you say, you first have to go hompe, find that notarized paper, convince the hospital lawyer that it means and likely you will have to repeat the process for each new hospital stay.