Ah, but Mitchell, the collapse interpretation doesn't explain why the Born probabilities are what they are.

So the version of many-worlds that I believe in, as a predictive theory, is:

(1) The wavefunction is real and evolves unitarily.
+
(2) For some unknown reason, experimental statistics match the Born probabilities.

In combination, these statements constitute a predictive theory.

As for the objection that (2) hasn't been explained, collapse "explains" it by tacking on, "And the reason for (2) is that parts of the wavefunction spontaneously vanish faster than light for some unknown reason, leaving only one survivor because we like it that way, and in the lone survivor, for some unknown reason, experimental statistics match the Born probabilities." If you look closely, this explains (2) by strictly containing it.