Two out of every three devices capable of running iOS 6 have already been upgraded to the software update. That’s a pretty astounding number, given the sheer number of iDevices out there in use.
Apple’s iOS 6 update hasn’t been without its issues, though it has had a remarkably smooth rollout. With the high penetration of iOS 6, it also means that developers will soon begin to update their apps to require the newest OS. Since Apple offers iOS 6 as a free OTA download, or by way of iTunes, for the majority of iDevices currently in use, developers will want to take advantage of the API and code changes that iOS 6 allows.
In other words, if you are preserving your current iOS 5.x.x build for the jailbreak, or for some other reason, it may soon be harder to justify the reasoning behind that.