It's not just about AWS, though. What about hard disk encryption, PGP, Bitcoin, or any other process that doesn't immediately leak its timing information over

It's not just about AWS, though. What about hard disk encryption, PGP, Bitcoin, or any other process that doesn't immediately leak its timing information over the network? I imagine it would be difficult to covertly leak LUKS keys on a massive scale via a compromised AES-NI implementation. It's not like you can just modify the ciphertext output, and anything that uses a lot of silicon would attract attention. On the other hand, a compromised RNG can do this pretty easily. Hell, NIST already published an algorithm that can do this.