I think it would be a shame if the Amiga moved over to X86, because like others have said Amiga would be just another OS rather than a unique h/w & s/w platform in its own right. I also like, and feel the need for a strong connection with the original Amiga kit from the 80/90s
PPc likely has enough legs to do most of what is required in the modern world - especially optimised for one platform. I wonder if there is any way of making the price more competitive? I guess it all depends on how you view Amiga computing in the modern world, e.g. hobby computing or a standard desktop work horse. As a work horse compared with the faceless stuff down PC World it is horrendously expensive, but as a unique, vibrant and interesting hobby it is excellent value for money with a great community behind it. I would say stop trying to compete with the mainstream and accept and enjoy 'Amiga' for its vibrancy, and uniqueness
I think a modern PPc card for the classic Amiga's would go along way towards getting more people involved and interested in OS4 - the market for classic Amiga seems very vibrant and well backed reviewing the price of second hand PPc cards etc. Also there are lots of 30+ year old kids(!) like me who are now in a position to buy that go faster turbo card we could never afford back in the day! But the connection -for me at least - would have to be there with the classic machines.
Amiga will win through as a unique interesting product steeped in History - as a standalone OS on X86 it will struggle because it would have little genuine connection with the past and only a very small developer base compared with Linux and Windows, in my humble opinion.
Stay original and niche!!