> Why can my 2008 Vista laptop be upgraded all the way to 8.1 and use software that come out today and my 2008 pocket computer / smartphone cannot do that?
In 2008 the 2nd gen (3G) iPhone launched. It had the same 400mhz 32-bit processor, 128MB of RAM, and 480x320 px screen as the 1st gen iPhone, so it basically represents the very beginning of what is now a six-year explosion in phone performance. iOS had seen a total of one year's public use. The App Store launched alongside the 3G -- outside of the tiny jailbreak community, no one had ever tried to write and sell apps for iOS before.
The iPhone 5S, released five years later, is roughly 50 times as fast,[1] meaning performance more than doubled each year from that starting point.
Give it another few years and your complaint will make sense. But right now, it would be a tremendous waste of time and potential to limit apps, APIs and OSes to what can run on the first round of iPhone hardware. Especially since, as far as I can tell, that hardware represents somewhere less than 1% of iOS phones in use.
[1] http://gabrieltomescu.com/blog/2013/10/25/how-accurate-is-th...