I'm mostly just handwaving "Miqo'te men are extremely rare" when it comes to RP. It's contradicted enough by the general player population and the RP community population that maintaining the assumption that male Miqo'tes are rare seems extremely silly.
But there are a few fairly simple justifications that I'd be more than willing to go along with, if I were forced to justify why reality doesn't reflect lore. For example, there could have been a major population boom among Miqo'te anywhere from ten to twenty years before the Calamity. The overall population of Miqo'te increased due to availability of resources, and more and more young ones have been leaving their tribes or clans to live life in the city-states or as adventurers. For reasons both related to intra-tribe cultural stability and gene pool diversity, as well as simply availability of resources post-Calamity, it would stand to reason that a large number of young adult Miqo'te have recently been encouraged or made to leave their more insular tribe or clan settlements in order to live in the big city or to become adventurers.
But there are a few fairly simple justifications that I'd be more than willing to go along with, if I were forced to justify why reality doesn't reflect lore. For example, there could have been a major population boom among Miqo'te anywhere from ten to twenty years before the Calamity. The overall population of Miqo'te increased due to availability of resources, and more and more young ones have been leaving their tribes or clans to live life in the city-states or as adventurers. For reasons both related to intra-tribe cultural stability and gene pool diversity, as well as simply availability of resources post-Calamity, it would stand to reason that a large number of young adult Miqo'te have recently been encouraged or made to leave their more insular tribe or clan settlements in order to live in the big city or to become adventurers.