Reprinting my Message from the CTO from the nineteenth newsletter so that you may comment on my thoughts.
As I write this, Google have just announced their NexusOne phone, featuring the next version of the Android operating system. Alongside this announcement are news reports about a recent ChangeWave survey that said levels of user interest and satisfaction in Android are now approaching that of the iPhone. Windows Mobile is falling behind ever more rapidly, fourth behind Blackberry. Suppose you're a smartphone application developer: which phone OS do you target?
To bring the question closer to home, since my readers are very likely to be PC or web application developers: which platform should you target? What if the choice you make or have made turns out to be the equivalent of Windows Mobile?
At some point, after you've done your research, you have to commit and implement your plans. And you have to continue with them despite what might be happening in the world outside that might be invalidating your assumptions. If not, your project might turn into Duke Nukem Forever, where the game engine was changed multiple times before the product was abandoned unreleased.
There are, I suppose, two strategies to minimize the risk: isolate the technology you're worried about behind an interface or framework and switch when necessary, or release early and often. The first might not be feasible anyway, and the second at least means you'll get some revenue and valuable feedback on functionality should a change in technology be required. Commit!
In essence, my thoughts here can be summed up to "release early, release often", but I'm surprised how often the same possible hesitancy can occur in other situations. An obvious example is buying a new PC: you know very well that if you wait a month, the PC you want will be cheaper, more action-packed, sleeker, but of course after a month you know in a month's time it will be better still. So you vacillate.
(Aside: to be brutally honest, the only times I've seen the "isolate behind an interface" option being used produced something that looked as if it had been designed by Architecture Astronauts.)