Again we are getting confused. There's a difference between dropping clocks and voltages when the chip is idle (when there's no workload to slow down), and dropping clocks/voltages when the user is loading the chip and waiting for it. What I'm talking about here is reducing clocks and voltages to prevent temperatures from exceeding a certain threshold while under load, reducing performance. Let's leave downclocking during idle out of the discussion.
The car comparison is poor here for too many reasons to list. For starters, sustaining maximum frequency is much more common for GPUs and CPUs. People run video games for hours every day, which puts the GPU at full load. Code compilation, rendering, image processing, simulations, some games, and even some badly designed web pages will put the CPU under sustained load. Almost nobody will hit their car's maximum rated speed. Every computer user will hit their CPU's maximum rated speed. And a lot of "power" users run workloads that will keep the CPU at that speed if surrounding components don't power limit or thermally limit the CPU. I've seen Intel CPUs draw way over their rated TDP at turbo, so I don't think the power limit (if any) is an issue. Usually I see clocks drop when the CPU hits some thermal threshold (upper 80s for a Surface Pro 3, 99 C for my older HP laptop).
The VID used has absolutely zero relevance to the discussion. Can we agree on that? I don't care if AMD shoves 3 V through the CPU to make it stable at that speed, as long as it lasts. What matters is that the processor is binned to be stable at that frequency, and be stable there for a really long time even under max load. If it's not, it should be RMA-ed. And if Intel/AMD/Nvidia put out a chip that became unstable at boost frequencies after being pushed there for sustained workloads, there'd be a ton of RMAs.
But yes, I get your point - Intel, AMD, and Nvidia do not guarantee turbo/boost clocks will be sustained (so those chips can be used by OEMs in designs unable to cool them if the chip was continuously run at the speed it was binned to be stable at). My personal gripe is just with paying for a chip guaranteed to reach a certain frequency, and then not using it there. I understand you guys are fine with that. I guess we should agree to disagree here.