An Interview with Scott Alexander

That's nowhere near a necessary or obvious conclusion. Even if it could "think a million times faster than von Neumann", there's no guarantee it could "beat any market", seeing as any market is contigent on thousands of non-predictable factor (from some earthquake in a manufacturing area, to a war breaking out, all the way to consumer unpredictability).

Even less so for "thousands of years of future events".

What is described is a magical prophet, not a super-intelligence.

And of course the idea that there's no diminishing returns limits to thought and you could "think a million times faster than von Neumann" or have an IQ of 10000000 or whatever is also highly dubious.