I think marriage isn't emphasized in Japanese modern society because women who don't marry and get married later in life increase with the increase in the ranks of working women.
I think husband and wife are best friend and respect each other. Being able to respect each other may be secret that maintain a lasting relationship. To have a baby isn't women's duty, but there is a need it because of solving the low birthrate problem. The omiai is one of the sexual encounter. We may be able to meet the ideal partner because we can meet a person who don't meet in an ordinary life.