The fdiv recall cost Intel almost half a billion dollars, and that was for a small subset of processors that most people didn't replace. Intel has a lot of assets, but replacing five years worth of CPUs might actually bankrupt them.
Maybe just average out the performance impact across large cloud providers and offer that as a percentage? It probably wouldn't be hard for a company like Google to crunch metrics before/after the update and give a number for how much their performance has been affected
I think the important thing here is precedent, rather than making customers whole. The question then is what, if anything, could Intel have done to anticipate and prevent this, and how do we incentivize them to take those measures in the future?
It's also possible that there's nothing to change here. There's always going to be some risk, and trying to force that risk closer and closer to zero will at some point not be worth the tradeoff. As bad as this is, if the caution necessary to prevent it would have resulted in processors being half as fast as they are today anyway, there wouldn't be any point.