I think the model for cloud vendors would be quite complicated. Not every version of the CPU and not every application is impacted as much (new intel processors with PCID will suffer less).

Add on top of that the fact that a lot cloud customers over provision (there's good scientific papers on how much spare CPU capacity there is). Cloud service providers that sell things on a per request / real CPU usage model (vs reserved capacity) prob benefit more.

Also, you can't just separate trading in AWS or GCE from the rest of the core business.

Potentially business units of DELL, HP, IBM, ... should do better as people use this as a justification to upgrade overdue hardware they should cover 5% to 10% lower performance (needing more units to cover that).