In contrast, the OP just presented a bare number, implying that it was high, but without any evidence for that claim.
And yes, there's lots of room for improvement. The model is very simple, the guesses at the Reddit thread sizes are 100% guesses (how long is the average comment? What's the distribution of thread lengths? Etc), I did some serious rounding here and there, trusted Google to do the math right (it is not that hard, but IEEE may be insufficient to get results that are somewhat correct, and I don't know what Google does), etc.
As to your "I never wrote nasi goreng in 500,000 words" argument: let's take my simple/flawed model. It predicts
(1-1/125000)^500000 ~= 0.018
Funny how you're trying to avoid breaking your streak of not mentioning nazis.