1. The poll results show a high correlation between income and responses.
2. It is a fact that the level of education (up to and including Masters degrees) are highly correlated to income. Beyond Masters degrees there may not be a continuing increase in income as PHD etc, are not as highly compensated as senior positions in business and politics and generally an undergrad or graduate degree is more sufficient for success in thos fields.
. 3. It is a fact that the level of education achievable is highly correlated to intelligence. Degree entry screening tests (e.g. SAT, GMAT, LSAT) are all highly correlated to IQ. In fact entry into Mensa (the high IQ club) is automatic if you score at the 95th percentile on the GMAT) and most good MBA schools won't let you in unless you score at the 85th percentile or better - as your ability to complete the degree successfully decreases with significantly the lower you score. 4. A IQ of 100 is unlikely to succeed in any Masters program (MBA, Law, medicine, etc), so I dispute you statement that a population of individuals with 100 IQ will earn at the same level as those with IQs of 120.
I assume you have data to back up your assertion?
Evidently you've not collected statistics on the number of PhD's and MBA's amongst the homeless?
LOL.