The future is already here
One important difference between the evolution of earlier smartphone platforms like Nokia's Communicators and Series 60 (Symbian) and the iPhone platform, to me, is that the development of the iPhone is actually _ongoing_.
I remember very well having the Nokia 9110 at some point. It was a great communicator, and for a while, it looked like future upgrades and additional software from 3rd party developers would make it an even greater communicator. Sure, a lack of GPRS or even HSCSD was a hardware-based problem that couldn't be solved in software, but the users expected to see more and better software features in the future. But Nokia didn't look at it like this. Nokia, after a while, simply abandoned the 9110 (after releasing the 9110i) and focused on the development of the 9210 (9290 for US citizens) - hardware- and software-wise. This meant that all that was left were a couple of hobbyists developing for the 9110 and 9110i, which basically meant that the platform was going nowhere. As with *every* communicator release, the 9210 was a move forward (colour screen, HSCSD) as well as a huge step back (slower GUI). And when it was released, it was already outdated without GRPS/EDGE support. When the 9500/9300 arrived, the 9210 platform was abandoned for the new Series 80 series communicators. But those again were left in the dust when the Nokia Communicator e90 arrived, which brought it to the Series 60 platform, which again was a step forward as well as a step back. Nokia wasn't and isn't offering software upgrades for the communicators to newer versions. Bugfix releases, yes, but software upgrades to really newer versions: No.
The 1st generation iPhone, however, runs 3.0 beautifully. Sure, the iPhone 3G brought along new hardware features like 3G connectivity and GPS, the 3GS brought a compass and a much speedier processor, but software-wise, the original iPhone can still keep up with (most) newer functions. Sure, they screw with their users as well (no MMS for original iPhones, what's up with that?), but not in a general way like it happens with the other platforms.
I'm sure some version (4.0, 5.0?) will leave the original iPhone in the dust, but by then most users will have moved on, anyway, and the others will either have bought their iPhone second-hand inexpensively (and probably won't expect every future update to work with their handset) or will be content with what they have, because after all, they've been using the great handset for _years_.
I've bought my first iPhone in late 2007. Some Swiss company imported AT&T iPhones on quite a big scale, and we jailbreaked and unlocked them using one or the other software that was around, so we could use it on Swisscom, sunrise or Orange Switzerland's networks. I then moved to the iPhone 3G when it became available with Orange Switzerland, my network of choice. Luckily, Orange offers one-year contracts for a bit more money than the usual 2-year iPhone offerings, which allowed me to move to the 3GS when it became available, and this _will_ allow me to move to the next iPhone next year, which is going to be great, I'm sure.
We'll probably see similar things happen to Android handsets. It doesn't seem like the users will be forbidden, somehow, to upgrade to newer versions of the operating system. And that's a good thing for smartphone users all around the world (or at least where the iPhone and Android handsets become available).
You can cry "lock in strategies" all you want, I never felt really "free" with the Nokia platforms or SonyEricsson platforms. Usually, those meant that you bought a device with a particular OS, and you were locked into _that_ until you bought a new handset.
With the iPhone I'm as free as I want to be. The jailbreaking community gives us options where Apple's a bit restrictive, but I must say I haven't been using jailbreaks on my 3G and 3GS, because the apps I needed and the functionality was available. (Other than push-notification, which only came about in recent weeks.)
I still wish the iPhone would go true multitasking (and I'm sure still missing one or the other additional feature), but I guess that'll happen with newer hardware and OS 4.0, or maybe with even newer hardware and OS 5.0 in 2011.