I think you're forgetting about all of computer users (Mac or PC)that use flash everyday in your equation.
(30 million iPhones and iPod touch + O iPads < 1 Billion Computers)
Apple has no leverage in this matter.
I'm not forgetting about them, but I'm suggesting that Apple really doesn't care. Why? Because they're putting all their chips into the consumer space, and increasingly into the mobile space. And they're focused on consumer activities such as web browsing, sorting photos, listening to music, watching movies, and so forth. I have a fast 24" screen iMac and a quad-core Mac Pro at home. 4 years ago, I probably used my desktop machines for 80% of my web surfing, and my laptop for the other 20%. 2 years about the split was more like 40% desktop, 30% laptop, and 30% iPhone. Now it's 20% desktop, 40% laptop, and 40% iPhone. In another 2 years, I would guess it'll be something like 0% desktop, 10% laptop, 20% iPhone, and 70% iPad.
I don't think I'm unique here, that is clearly the consumer trend. People are using their desktops less and less each year, especially for web surfing, and many people aren't even buying desktops anymore. Why fire up my laptop when I can pick up my iPad and already be at the site I want before my desktop wakes up from sleep? And I can move around with it as well.
The bottom line is I think Apple is so confident in the trend towards the new kinds of devices they make (iPhone and now iPad) that they're betting in the majority of people web surfing happening on these in the near future. And as John Gruber pointed out a few days ago, there is an installed base tipping point where Flash becomes irrelevant and eventually isn't needed at all. In 5 years, if only 75% of devices that people are browsing on support Flash, is that enough to keep it alive? I don't think so. Flash's strength in the past has been its ubiquity, and as soon as it's non-ubiquitous, it's going to lose support. 10 years ago, how many people would have predicted Microsoft would be eclipsed by Google and Apple?
It's a gamble for Apple but they may end up winning this fight.