I don't think comparing meteorology to this is completely fair. If I would be an investor considering where to invest these (I would assume) big amounts of money I'd be thorough and do my research, look in the playerbase itself for clues to the succes of a game/company.
I actually thought the comparison to meteorology is quite accurate, because statisical analysis generally relies on regression/correlation.
Personally, I have no opinion about this prediction as I have no idea how they obtained this number; the factors they used, the method they used, what data they used, and so on, thus without this background informaton the number '5 million' has no meaning to me. And even then, a prediction like this is never(or rarely) 100% accurate.