Why didn't Apple support Adobe's popular Flash plugin way back in 2007 when it first launched the original iPhone 2G? Because Adobe still can't get it to run on the most powerful, most modern 2010 devices Android, Palm and others have to offer. That's why.
"We have a number of excited partners who are working aggressively with us to bring Flash to their devices, whether they be smartphones as well as handsets, and so companies like Google or RIM or Palm are going to be releasing versions of Flash on smartphones and tablets in the second half of the year."
Maybe Adobe will finally get it working in Q2 2010, but we've heard that "it's coming!" line once too often now, so forgive us if "partners working aggressively" gives us a something diametrically opposed to confidence.
The facts remain, however, that the iPad will run HTML5 video inline today (and iPhone OS 4 this summer) without even getting warm to the touch while our laptops and multicore desktops turn into noisy miniature blast furnaces when the plugin spins up on their far more powerful hardware.
Flash, like Internet Explorer 6 and ActiveX filled a need and became a popular if proprietary and problematic solution. Years without competition finally caught up with Microsoft by way of Firefox and WebKit, as it's now catching up with Adobe by way of HTML5. Many years and incredible loss of mindshare later, Microsoft is scheduled to finally ship a standards-compliant browser with IE9. Maybe Adobe can work a faster miracle with Flash. But even if they do, HTML5 will have had months of mobile video delivery under its belt on a platform Apple predicted in their iAds (which also uses HTML5) introduction will soon be 100,000,000 strong. That's a heck of a head start and Apple is not a company known to look back.
You didn't have Flash on the iPhone in 2007 for the same reason you don't have Flash on any mobile device outside a Nokia netbookphone today. For the same reason you can't jump on a Corellian star-freighter and hit hyperspace for Endor. The technology doesn't exist yet, and when and if it ever does, for Apple and the iPhone it will likely be too little, too late.