Society imposes a very heavy fine for the breakup of a marriage and it becomes a huge gamble.
Either it will work out and you'll be happy and you'll recommend it to everyone.
Or it will destroy your life.
If marriage was "cheap" to establish and break up people could do it naturally and peacefully, eventually and successfully move to stable ones if the first attempt doesn't work out.
When the risk taking a particular action gets high enough it's completely understandable why many rational people would avoid testing their luck.
Either it will work out and you'll be happy and you'll recommend it to everyone.
Or it will destroy your life.
If marriage was "cheap" to establish and break up people could do it naturally and peacefully, eventually and successfully move to stable ones if the first attempt doesn't work out.
When the risk taking a particular action gets high enough it's completely understandable why many rational people would avoid testing their luck.