But this is an electrical problem. Interference is a huge issue with any engineering that involves physical things and these kinds of attacks are just interference problems. This issue is no different from a microwave knocking out your Wi-Fi. These attacks have become possible because the acceptable interference threshold that chip makers have been using has turned out to be too low.

How do you fix interference problems? First, you choose a new threshold of acceptable interference and then you engineer better isolation, you lower density, and/or you switch technology.

We could make shared computing complete safe tomorrow if we wanted to so I think calling this the end to shared computing is quite alarmist. The issue is that we collectively want to both have the cake and eat it too: we currently have a certain cost-to-compute ratio that we have become accustomed to and we don't want to compromise that. We're basically buying time until we can invent a new technology that can achieve the same density without the same level of interference.