Yes, X86 is a logical choice based on available hardware. But AmigaOS is a closed source OS with a handful of people working on it, the market is small, it's not a general interest OS. There's no audience of millions waiting for the Amiga line, there might have been in 1995, but they've long since left the station. AROS and Anubis have taught us that.
It 's us and a handful of retro enthusiasts that might join us. That means they for the most part are willing to pay a premium. So why bother porting to X86?