The MO have more older singles from both genders. So even if there’s an age gap, it wouldn’t be as noticeable, or “the issue”. The issue for many of them is, and correct me if I’m wrong, singles too busy to get married, and not motivated enough to find a life partner to settle down with. Unless we do real studies, only once most 20-30 year olds are married can we get a better picture of what percentage of each gender the remaining “pool” consists of.
Of course I’m generalizing here, so I may get a beating for my statement. Here’s the disclaimer: there are many exceptions, and the more religious ones likely get married sooner.