Remember, even though it was 70k miles, it was also how many years?? Simple age can cause a belt to start cracking. Honda probably chooses their intervals so that only a tiny fraction of a percent (six-sigma) will fail. (probably little consolation to the 3 out of 1 million owners who's belts fail inside the interval)

 

The car was purchased new in 2007 and the timing belt changed the end of 2015 which made it 8 years old in a hot climate.