Making marriage the norm would not fix any of the issues I see in my own society, and marriage causes other problems.

Many people I know (including solo mums) that I know would love to find someone worthwhile marrying... However they haven't (or can't) find someone worthwhile, so it is better to remain single than get married into a dangerous relationship.

I suspect you are mistaking cause and effect. Marriage isn't a cause, it is an outcome.