That sort of chip spec sounds superficially plausible - and the sort of thing that Apple would need to replace Intel in the MacBook Pro (you wouldn't stick an A13 in a higher-end MacBook
Pro although you might get away with it in an Air). Sounds mainly speculation though - just riffing in the Intel leak from months ago that they
expected Apple to start moving to ARM in 2020, which could just have been Intel worst-casing as part of their "due dilligence".
Totally disagree on this "mobile/laptop bridge" thing being behind the shift to ARM, though. You do *not* need to shift to ARM to interoperate with mobile,
because mobile applications - and other non-legacy apps - don't generally give a wet slap about what CPU architecture they're running on.
Android apps are predominantly shipped as bytecode for the Dalvik virtual machine, "modern" MS Windows apps are increasingly compiled to bytecode for the MS Common Language Runtime (which has been a thing since .Net came out) and while I believe iOS Apps
are still shipped as ARM binaries, for anything capable of getting accepted into the App store that is a tick-box in Xcode - in fact, iOS apps are tested in Xcode by compiling them to x86 and running them in a "iOS x86" sandbox. That's not counting the increasing amount of stuff written in "script" languages like Javascript or Python. When the source code is identical, maintaining multiple binaries is no biggie, especially when everything
has to be distributed by an online App store.
So, at least for "modern" apps, the days of letting your applications choose your processor architecture are coming to an end and the only people who need to worry about whether the target has an ARM, x86 or RISC-V (esp. when everything is 64-bit and little-endian) are the systems programmers who write compilers, VMs, drivers and runtime libraries.
The issue keeping x86 alive is established "desktop" (as opposed to mobile) apps that still contain a lot of legacy code or - for some other reason - implement their own drivers and/or eschew the official OS frameworks. (...and for some users that includes x86 Windows virtualisation - which will probably be the biggest issue for ARM Macs).
Microsoft made ARM-based computers for a long time and yet they are totally failures due to lack of compatibility and performance eve in 2019. So I wonder if Apple can manage to make a proper ARM-based Mac in 2020?
Microsoft has a huge albatross around its neck in the form of legacy applications, including a vast amount of ancient in-house written software in the corporate market - if MacOS is nicer than Windows that's a big part of the reason. They've faced a massive uphill struggle to get rid of Windows XP - and many of the faults in
that (e.g. everything running with Admin rights) were because it had to run apps written for DOS and Win3.1 and Win9x ...and really old x86 code, even in C, can be
really non-portable, since early DOS/Windows wasn't properly 32 bit and those OSs
didn't have such extensive hardware-independnet frameworks.
Apple don't really have the corporate drag-anchor and can be much more flexible - has already
completely switched OS once (Classic MacOS to son-of-NextStep-aka-OS X) and processor twice (68k to PPC, PPC to Intel - thrice if you want to count 6502 to 68k). Over the last year, they've thrown 32-bit support under a bus and declared OpenGL obsolescent (I'm sure MS
dream of being able to do that). Dropping 32 bit in itself has probably cleared out a lot of the "dead wood" that would hamper an ARM switch.
But yeah, the performance won't be that good initially.
As long as its running "modern" apps which don't need x86 emulation - a MacBook
Air with that chip in is likely to smoke the x86 Air. Even a Rosetta-like 'just in time' x86-to-ARM translator might be pretty slick with software that makes good use of Metal, Core Audio, Accelerator kit etc. rather than hard-coded Intel SIMD etc. calls. Its going to be waiting for things like Adobe CS and all your third-party graphics/video/audio plug-ins that will be an issue (but that's not really what people buy an Air for...)