Some thoughts I have had on this subject
When young and planning a life you try to find someone who's goals align with your own. Marriage minded, buying a home or renting, kids or not, travel, hobbies and activities, lifestyle, etc., etc. But when young many of the future plans are just that, a plan and not a reality yet, so you marry based on hope. Sometimes we even discover things we personally wanted arent what we thought. As we know many plans never work out, and we change as we age, and that's why many marriages fail.
As older adults we have a person's actual history to look at, and our own, and more than likely seniors aren't going to change much, we are who we are. So now we can take a look back at how a person lived their life. Did they travel? Did they like owning a home? Were they financially prudent? Did they quit the bar scene? As a senior you don't have to just hope for the best, you have a factual history to look at.
That in itself, marrying based on facts instead of hopes makes finding the ideal partner less likely.
Not sure if I explained myself very well, hope my point is understood.