Isn't that assuming that fix won't be implemented?

Zero days are valuable because they can be exploited but if the pace of exploitation is faster (which I'm not sure is the case), then the response WILL be faster, even if it means going offline. Institutions that won't will simply go offline by losing their data or becoming unprofitable due to ransomware.

Now for components that are core to the infrastructure, say OpenSSL, there is already a TON of attention and efforts, including red teaming, so it's not as if it's opening floodgates.

Sure low hanging fruits will get picked either faster or a at a larger scale, say a random outdated IoT device at your local flower shop, but for the rest, I don't think it's realistic to expect no response.

Security, digital or not, has always been an arm race. New threats means new responses specifically by incorporating the threat.

As compute prices fall it gets easier and easier to make "frontier" models. So it's inevitable that commodity, open source models of equivalent capacity to today's "frontier" models will be available to the public. Remember this is just weights, anyone can download them and run it whenever they like. The only constraint is compute.

depends on the blast radius of zero-days, it's not like there's a continuous immediate release process for these models; they can eval internally before releasing publicly

I haven't heard of the term "chaining zero-days". Now as a SRE I wont sleep.