Arranged marriages are also a way to unite families, whether they were particularly disharmonious before or not, and therefore were probably often engineered for resources more than the really obvious genetic factors. Wealth (and indirectly, the ability to obtain wealth) running in one's family netted the ability to secure a similarly wealthy/wealth-obtainment-advantaged spouse. Irresponsible "bad" people probably had (have) all of their children via non-marital encounters in societies where arranged marriage was (is) common.