Two is too many, I agree, but it will almost surely be 1 in the next coming months (assuming Microsoft supports WebM + VP8)
Hypothetically were IE to ship with WebM support, Apple doesn't have the market share to enforce their current codec monoculture. The converse is not true however; Microsoft doesn't care if Safari/iOS can play WebM. The onus is thus on the IE team, and I think Apple is irrelevant to the issue.