Try building Meltdown on purpose! Who will know? How do they defend design choices to those who can't know? Nobody can afford this in breadth. Granted, you can

Try building Meltdown on purpose! Who will know? How do they defend design choices to those who can't know? Nobody can afford this in breadth. Granted, you can manufacture a rigged batch and keep it secret. But you can't have a broad capability and expect it to remain secret for long.