There are two ways, both of them disturbing and unsettling, by which a society of zero social mobility could simultaneously satisfy FEO. One is that the rank order of each person's genetically given native talent endowment mirrors the rank order of each person's family of origin income. If there are 100 persons in the current generation of individuals and your native talent endowment is overall 40th-best, your family of origin income is also 40th-best, and the same holds for every other member of the current generation. If any two people in society have the same native talent endowment and the same ambition, they have the same prospects for competitive success, and their family of origin incomes will also be the same. Another possible mechanism is that ambition formation tracks family of origin income position (via some process that does not itself violate FEO), so that no persons with the same native talent endowment and different family of origin incomes have the same ambition, so their having different prospects of competitive success does not violate FEO. There could also be social dynamics that involve mixes of the two ways to produce satisfaction of FEO along with zero social mobility.