The odds of winning a lottery (lets say the Mega Millions or the Diversity Visa) are, to an extent, evenly distributed. The odds of succeeding in a social endeavour (lets say a business or a Green Card obtained via application) are not.

While on average the odds of the latter (the business) may be better, for a given person (which is always me and never an average person) the odds of the former (the lottery) may actually be much higher.

On a side note, while it may seem "un-meritocratic" to the HN crowd, having lotteries as gateways to social mobility and resource allocation is a decent idea.