"Awkward" and "wordy" are my least-favorite terms in SC. They are only helpful if you already know the answer is wrong and would like a quick way to justify your choice!
Since "equal to" follows the noun "people," it implies that the people themselves, not the numbers are equal. Far be it from me to deny the equality of all people, but I don't think that's what the author was talking about.

"As many as" is tricky, but basically we need to modify an action: "as many as were present at the Super Bowl," "as many as I met yesterday," etc. It would be odd to say "as many as the people in the rest of the world," because then we're saying "these people are as many as these people," and that's not how we typically use the word "many."
However, this is a rewrite of an official question in which the meaning issue is a lot clearer (look at daagh's "Most Helpful Reply" right under the original post). As so often happens when folks rewrite a GMAT question, the very specific factors that made the official answer 100% right have been lost. If you look at D in the original, you should have much less trouble ruling it out!
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