Do you think if iphone had flash, developers would go through the trouble of app betting process by apple? Every streaming music service, video service and flash games and applications would make Appstore irrelevant.
That, in my opinion, is the single biggest reason why we will _never_ see flash support in iphone of ipad no matter how fast and secure flash becomes in the near future.
Not that I care about flash in mobile device. But, using performance as the main reason for not supporting flash is silly. It can be one of the several reasons, but definitely not the main reason.