The original report is just speculating, why would Apple drop the 1 year old 5c?
The 5C is the replacement of the 5, which is three years old this fall. To treat it like it was brand new when it first came out is silly and not exactly fair as that's not even how Apple positioned it when it was released.
Also, their speculation means far more than our speculations.
Apple still sells A5 devices. If they didn't want to support A5 they would've dropped the Mini 1 by now.
The fact that they still sell it today means nothing; Apple has discontinued OS support for devices that were sold in February of the same year that they lost OS support; this is not a new trend. If they're still selling it by the time WWDC rolls around then that'd be a whole new precedent to be set. That being said, if this is an update a la Snow Leopard, they are almost guaranteed to drop A5 support. I agree that also dropping the A6 seems hasty, but if the whole point of iOS 9 is to solely focus on 64-bit ARM so they can streamline things, then I can see them cutting off support a year early. Apple's not one to care if you're holding onto an old device.
My guess is that it was decided at some point that they want the A5 to support one more version of iOS than previous chips. Just like the 3GS did.
Their end goal isn't longevity of device ownership. That's not how Apple makes so much more money on iPhones than they ever did on iPods. Their goal is to have a marriage of software and hardware that is the best thing out there. They are already having to bend the code backwards to retain iOS 8 support with the A5 and, I'm not sure if you've ever owned or used one of those devices running on that OS, the experience leaves much to be desired. If the A5 lacks support for the technologies that they want in iOS moving forward, the A5 will be dropped. Same goes for any other processor that isn't doing what Apple wants it to do with regards to future versions of iOS.
People are only reading one half of the "it's gonna be like Snow Leopard" story. That one half is fat-trimming and optimization; and if that's all Apple was going to do, it would be fair to assume that the A5 would get one more year. However, the second half that barely anyone on here seems to be paying attention to is under-the-hood technology overhauls and enhancements, which have historically eschewed the hardware on the older end of the prior OS's minimum system requirements. With Snow Leopard that meant the removal of support for 867MHz and faster G4s, and all G5s, which ran Leopard about as well as the A5 CPUs run iOS 8 today.
So, yeah, odds aren't good that the A5 will retain support even if we still have two A5 devices still sold today (one of which is on a very-clearly abandoned product line [iPod touch] and the other is on a product line that is very quickly headed down the same path [iPad mini] if the critical reception of this past October's update is any indication at all). I'd say that A6 will lose support ONLY if Apple decides to have iOS 9 and beyond be exclusively 64-bit (which isn't something I would put past Apple to do); otherwise, it's likely that the trend will continue as it has for the past couple years of iPhone and iOS releases.