I think this goes far and beyond Enterprise play or anything of that nature. There is a lot at stake here.
This is a response to a bigger paradigm shift that is the web and software as a service and Mobiles.
If you are on Windows XP and windows 7 rolls out, you have the option of upgrading, not upgrading or switching to a Mac (or similar).
Gmail versus outlook is another good example. With Outlook you would need to shell out big bucks and wait for the next major release. A three year release cycle has really got to suck for the team. If your team's major feature X didn't make it in the current release, you could very well end up waiting another three years. Gmail's releases by contrast are liberating.
The Chrome browser versus IE is another glaringly obvious misstep. One doesn't even care about version numbers anymore and releases indiscriminately while the other feels like an antiquated behemoth that rears it's ugly head every few years and then goes back into hibernation for years. It's a shame, really.
The mobile landscape has shifted to something similar. My upgrades on iOS come seamlessly and effortlessly. Apple can push whatever it wants down upgrade pipeline without costs.
For years desktop companies have relied on pushing the hardware limits to force users to upgrade their hardware, followed by the operating system and consequently all the software running atop that OS. It has been a tremendous boon for every Windows-based software company, almost guaranteeing fresh inflows every three years. So this is going to have an impact on the entire ecosystem.
From a developer's perspective:
Software rewrites cause regression. Microsoft has been regressing all over the place, for years now, most prominently with their Windows releases. For anyone who doesn't write software for a living, regression happens typically when you rewrite a piece of code and in doing so reintroduce old edge conditions or have to re-tweak all the features around it. Only after that does the new rewrite start paying dividends.
Continuous release cycles sidestep the regression issue to some extent by making the iterations smaller and the features less jarring for the users (Windows 7).
As a consumer:
I like the AppStore model because it doesn't charge me for versions (I know that might note bode well for developers because lifetime revenue per app becomes fairly static. A good friend of mine is just completing a rewrite of his app and his entire existing user base will probably end up getting it for free. However, this is still the option of IAP, product SKUs or subscription models).