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Of all the coins in the history of the world that have been flipped 21 times heads in a row, I'll bet none of them were fair.

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I think "none" is a bit strong, although its not a bet we would be empirically able to resolve.
I take the general point about there being an increased likelyhood of bias either in the coin or its flipping.
The likelyhood of any such bias however is also determined by many other factors.

Analogous example:

Home game: my opponent is dealt two straight flushes and a royal flush. I am dealt the ace high flush twice and a full house the third time. This happens in three consequetive occaisions when my oppenent is dealer.

Do I suspect he might be cheating?

Party poker 1/2: same thing happems. Evem down to the dealer button being with him on each occaision.

Do I think Pary is rigged, or that he has cracked their software?

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"none" is absolutley not too strong a term. It is physically impossible for a coin to be precisely fair. Also, atmospheric effects are constantly changing, so even if a coin could somehow be fair on one flip, it would not be fair on the next.