Jelly Bean will be released in two weeks, at the same time with the first Android 4.1 device, the Nexus 7. The Galaxy Nexus, Nexus S, and Motorola Xoom should be getting the updates on the same day, or shortly after. This will be a great time for Nexus devices owners, who will get to use Google's latest and greatest version of Android.
Unfortunately, 80% of the market is still on Gingerbread (63%) and Froyo (17%), with only 10% being on ICS, which was launched 8 months ago, and another 10% or so being on older versions or Honeycomb.
On one hand, I think many Android users and many people in the tech press underestimated how hard it is to change for manufacturers to change their core code from Android 2.xx to Android 4.xx. It's not coincidence that, even after all this time, the best custom ROM makers out there, the CyanogenMod team, still hasn't made its ICS ROM stable. Even if CM9 will arrive soon (they've just released the RC1 version), it probably still won't include a stock FM Radio app, because of the necessity to ensure compatibility with a vast array of devices. I'm sure they will do it eventually, and until then you can use the Spirit FM Unlocked app as a workaround for some phones.
But the problems faced by the CM team are a statement about how hard it must've been for manufacturers to upgrade to the Android 4.0 codebase. So, from this point of view I understand why manufacturers took a lot longer to upgrade to Android 4.0.
On the hand, there's no excuse for them to still be releasing phones with Gingerbread at this point (I don't think I've seen one over the past two months, though). I don't care about them saying that they were already working on devices with Gingerbread by the time ICS came out. Even if they started work months before, they would still had plenty of time to switch to the new OS. Also, maybe they shouldn't release so many models and versions of the same phone, if they can't handle porting the latest version of Android even in eight months. So I put the blame fully on the manufacturers for this one.
I'm glad Google has finally solved Android's performance issues with JellyBean, and even though I'm excited about it arriving on high-end phones, I'm even more excited about it arriving on low-end phones, where such a huge increase in performance would be very welcomed and noticeable.
People all over the world that do not care about or can't afford high-end devices will still be able to get a very good experience with Android 4.1+ devices, even with low-end processors.