Google: Software is never going to be able to fix Spectre-type bugs

I remember when these attacks first came out that a few people were saying, "speculative processing was a mistake, we should just eat the performance costs and get rid of it." I vaguely remember that position getting a lot of criticism.

Is that where we are though? Are the performance costs of abandoning speculative processing greater than the performance costs of relying on spinning up a new process every time you want sandboxing to work? Or is there a middle ground that I don't understand? Obviously there's a lot of old hardware that's never going to be replaced, but let's say I sit down today to build a new processor for a new computer. Do I just accept that it will be vulnerable and move forward anyway?

My naive reading of this is that Google is saying we need to rethink processors themselves if we want to fix this (and we really do want to fix it). Am I reading it correctly?

What I don't know is the actual real-world potential for data theft. IIRC, the data could only be stolen at a few k/second and you would need to know which address to start poking at. If my sister-VM has 64GB of ram an 64GB of swap, what are the chances of finding anything before the end of time?

Their experience, literally, was, "we tried to fix it and the whole Internet yelled at us".

I believe a practical (if oversimplified) model of the trade-offs is more like "secure, useful, fast: pick two".

So this is yet another reason to avoid Javascript.