Just because some people choose to exclude themselves from the dating market doesn't mean that the market doesn't exist. Everyone has standards of exclusivity when dating, even if they are only excluding the people who are very very physically unattractive, mentally unattractive, least capable, unintelligent, boring, etc. Not everyone uses the same exact standard to judge everyone else's attractiveness. For example, women on average tend to be less focused on physical attractiveness. But even when a woman is attracted to someone physically unattractive, that person usually has some time of other factor of attractiveness, such as status or personality, which other women find attractive as well. There are exceptions but the fact that those exceptions are so few and far between only proves the rule.