Microsoft got credit for ripping up Windows Mobile 6.5 and hitting the reset button: unfortunately it seems to be trying to do the same with Windows Phone 8, leaving early-adopters behind. The news from the Windows Phone Summit today that existing handsets won't get WP8 but will, instead, get a partial upgrade called Windows Phone 7.8 with the new Metro Start Screen but not much else means everyone who has supported Microsoft and its OEM partners so far can't expect much in the way of software longevity.
Instead, Windows Phone 8 will require new hardware. If you bought a Lumia 900 recently, for instance, the flagship Nokia Windows Phone on the market today, in just a few months time it will be outclassed by new devices and, most gallingly, be instantly left behind in terms of the new functionality.
Windows Phone 7.8 does have some advantages, at least in the short-term. Microsoft's decision not to offer Windows Phone 8 for existing devices is presumably based on hardware limitations for the current specification guidelines: the new Windows core is likely too demanding. If the company had pushed ahead anyway then it might have led to a seriously sub-par user experience overall, something that presumably won't be the case with v7.8.
It's what comes afterwards that's questionable. Microsoft, unsurprisingly, hasn't talked about what 7.x releases are expected after v7.8, but it certainly seems likely that the company will push ahead to only working on 8.x iterations. Less than a year into your Lumia 900 agreement, you're most probably left with a device that's unlikely to see another point-upgrade in its lifetime.
Windows Phone 8 looks like a solid and interesting platform, particularly in terms of the tightening ecosystem between it, Windows 8 and Xbox LIVE. That's great for new users, certainly, but those who have already taken the leap and jumped on board with Windows Phone 7/7.5 are in an altogether more frustrating position. Leaving anyone behind when you're playing catch-up in the smartphone segment is not something to be proud of.