I see a combination of things equally as barriers. Age, past relationships, family, morals, and standards.

Some women will settle for less to have a man, many due to finances. All my friends and myself do not need a man for that reason. That could be a barrier right there. I just don't know.

Many of the men I have gone out with wanted sex before thy even knew your last name! That's not for me. Is it because of my age? Quite possibly.