Apple announced the iPhone 5s last week, which as some will remember, has an A7 processor and support for 64-bit. This of course brought the follow-up chatter regarding the move to 64-bit on the mobile side. We have already heard from Samsung on the topic. Samsung has pledged future support for 64-bit, however despite Apple already having made the official announcement, it looks like Android may not be that far behind.
In fact, according to a recent ars technica report, Android is already capable of 64-bit processing. This all ties in with how Android is based on the Linux kernel. And well, Linux has already been supporting 64-bit for several years now. The report cites Linux Foundation Executive Director Jim Zemlin who said that 64-bit support is "done in Linux." Zemlin then went on to talk about how "the Android ecosystem just picks that up by default."
The key here is the other companies such as Samsung to make good on those promises and offer devices with 64-bit chips. Then from that point things would shift towards the developers. They would need to begin building apps that would be able to take advantage of the technology so the end users can begin experiencing the potential benefits.
Needless to say, this will all take some time. Not to mention we would first need Google to begin offering some support for 64-bit development. For example, new tools that will allow developers to rework their apps to support the new setup. Similar to how we saw Apple talk about how they updated their core apps, we would expect Google to do the same.
In the end it seems 64-bit for Android is just a matter of time. Basically, it seems as if we should be asking when this will come as opposed to if this will come. That does bring the question as to whether Google will make any kind of 64-bit announcement when they offer more details on Android 4.4 Kit Kat.