That could or could not be correct. We don't know their bill of materials. Probably some people can estimate it better for Intel. I understand the ARM stuff is AWS proprietary, so I would be surprised is any figures are public. Besides the costs are unkown the margins could be very different. AWS might be willing to pay a high investment to get more independent of Intel in the long term.

I worked at a big corporation in the mobile space before. They were willing to pay a high investment to get more independent of their single ARM SoC supplier. (It failed because Intel could not deliver in the end.)