> If there was a genetic component to "super-intelligence" then we would observe it. How many of those great minds listed had parents or children that also made the list: zero.
High intelligence and other forms of talent certainly run in families. If you read bios of scientists and mathematicians (as I am doing now, actually, in reading the Albers compendiums of interviews with mathematicians, _Mathematical People_ and _Fascinating Mathematical People_), time and again you find that a great mathematician has mathematician relatives or family which were talented in other ways. Consider the Bachs, the Polgars, the Wieners, the Bernoullis, the Darwins... Remember one of the origins of research into intelligence: Galton researching English geniuses and noting they were often related. Such clustering is consistent both with environmental and genetic explanations, of course, but no one argues that there is no clustering at all!
> Also, would any of these (suspiciously all European) super-geniuses have been as successful if there were born in a small backwater village?
Many of them were. Murray in _Human Accomplishment_ notes that of his eminent figures, while they all tended to gravitate towards capital cities like London and Paris as young as possible and live and die there, they were often born in the countryside. (An extreme case of rural talent being discovered is Ramanujan.) This should be no surprise to you since urban populations have historically been a small fraction of total populations and so naturally a lot of great figures will hail from outside the cities.
> There are probably millions of people with Einstein-level intelligence around the world,
Maybe.
> but living in environments that are hardly conducive to the expression of their genius.
Yeah, no. Environments can't produce geniuses, but they can certainly prevent them. The mean IQs of places like India do not indicate many of their citizens are as far out on the tails as Einstein...