It's not circular logic - ports of AAA products won't be designed for ARM because the current AAA products aren't designed for ARM. New AAA products won't be designed for ARM, because ARM doesn't have a history of AAA products that you can point to to demonstrate to the money people that AAA titles are worth it on ARM
a ton of major gaming products designed for ARM - the DS, 3DS, and PS Vita are all ARM based.
Handhelds. Not AAA domain.
Most major gaming engines support both: Unreal, Gamebryo, Blitztech, CryEngine, etc
You really overestimate the "write once, run everywhere" nature of game engines.
ut of every generation of consoles to date, this seems like the one for which porting will be the easiest - support for porting between ARM and x86 is certainly at a much more mature state than porting between PowerPC (Xbox 360) and Cell (PS3), for example.
It will be the easiest... because all AAA titles will be ported from XBox (x86) to PS4 (x86) to PC (x86). All indie games will be published across all platforms that they can push to.