His point holds only if the society never converts to polygamy. This is true in a period of time during British history in which it was written. However, you

His point holds only if the society never converts to polygamy. This is true in a period of time during British history in which it was written. However, you would assume that over the period of one generation, if there were consistently more women than (suitable) men, the society would begin to accept multiple marriage, first tacitly, then finally explicitly. Or, as we experience in today's society, single mothers. Once shunned, then accepted, now supported. In fact, because of the surplus that modern society now generates (and thus is able to support single mothers, for the most part) single mothers can succesfully raise a family. In a modern society with a surplus of women and a deficit of men, widespread single motherhood is more likely than polygamy. Thus, successful men are going to have multiple partners, but might not stick around to support them.