I routinely tout the high adoption rate of iOS devices and how it justifies increasing the minimum iOS versions for apps because you still have a massive potential userbase. But because Android has more phones in the marketplace than iOS is it possibly now for developers to make Android 4.0 the minimum and still get a respected number of users?
There's no easy answer to that question because it depends on what your target use case actually is.
Remember that the goal of Android is to be a universal platform for hardware, which means that the target devices for Android are much more heterogeneous than iOS - and therefore the intended use case as well.
I use an out-of-date Android device as a portable music player and an up-to-date one as my regular phone. Even that's not that wildly different if you start imagining people running Android on their household appliances.
So, in my case, even though I technically still run Gingerbread, I'm fine with Android applications requiring 4.2+, since the only device that runs Gingerbread is essentially a single-purpose dedicated device. I imagine we'll start to see more of this behavior in the future.
I'm not exactly sure what you mean by this. Do you mean consumers will use/buy older Android devices for very specific tasks?
I think the exact opposite of this will happen. Your average consumer is not going to want to have multiple devices. They just want to carry their phone around and have it do everything for them.
Your "average consumer" already does. The point is that Android in three years will be serving an even wider range of devices and household appliances.
While I agree a lot more devices will be running a more complicated OS with increased capabilities in the I future I don't think it is a foregone conclusion that it will run Android. Android is primarily used on phones, tablets and TVs because of explicit design choices made. Perhaps they will position themselves as a generic OS for electronic devices but they have some work to do before that can happen.
Your microwave currently has a home-rolled LCD+pushbutton interface. Within a few years it will be an Android powered touch device. Probably out of date before you buy it with no way to update.
But who cares, right? It's a microwave. As long as it still performs its microwave controlling functions, it doesn't matter if top new Google Play apps don't run on it.
I'm not 100% sure how realistic this is. But I have a feeling it's close.
When I upgraded from Gingerbread to Jelly, I liked the improvements a lot, but it wasn't enough to justify the decreased battery life. Granted I'm talking about a Galaxy S, with Jelly coming from Cyanogenmod, which is known to have battery issues because of shitty drivers.
So I'm just waiting for a phone upgrade when my contract expires. My next phone is going to be a Nexus, because that's the only phone guaranteed to receive supported upgrades for major versions. On the other hand, my Gingerbread has served me extremely well, which is why I don't really feel the need to upgrade, otherwise I would have done it already.
All users are going to upgrade to Jelly or higher eventually, because contracts expire and batteries die.