I don't understand what you mean. They've always been making progress, driving the price up. They can just keep doing what they're doing, and there will be progress from today.

Is that actually true? Has the price of these exploits been going up year after year, or has it topped out at some level?

It’s been going up consistently. The number of groups that can field a full chain these days is dwindling.

Perhaps Apple should provide research devices directly to the US's and China's intelligence agencies and pit them against each other to help close more vulnerabilities. The agencies can decide on their own where to strike the balance between offense and defense, but I suspect it would lead to more closed vulnerabilities over time.

Intelligence agencies unfortunately seem to have a bad track record when it comes to disclosing vulnerabilities, they’re very offensive-focused.

I think that would be the case if they were given to the US and other Western intelligence agencies. My scenario requires competition between geopolitical opponents to create an incentive to worry about defense as well.

Yes it has been going up.