Zen 3D, not even a paper launch in December... tsk tsk tsk.
I can't believe any consumer would want a paper launch.
Companies would also have come to know that after all the disappointments with availability that we've had for the past 2 years, if they did a paper launch, the tech media would rip them a new one.
They might be hedging on their newer architecture staying as comparatively efficient as they currently are. Why do 8C+8c when you could make 12C just as efficient and have better performance? For mobile processors, Alder Lake would need to have an almost 20% improvement in power efficiency over Tiger Lake which is on the same node, just to match the efficiency of current Zen 3 processors on the market, in my experience with the latter two.
You can fit 4 small cores in the space of a single big core, so your math doesn't hold up in terms of die area and therefore cost. It would be 8C+8c versus 10C.
Efficiency isn't a single number, but a range that will differ based on the workload's intensity. Getting good efficiency out of big cores requires higher utilization. At low utilization, most of the big core is going to waste and it's consuming more power.
Little cores aren't about absolute performance, but low power for background tasks/idle - this is important for laptops and for companies that deploy thousands of computers in their offices sitting at almost idle most of the time, just displaying Excel etc. The benefit doesn't come only from less energy consumed by the computers or office A/C, but also corporate environmental requirements. It helps with greenwashing PR as well. See companies advertising that their operations are carbon-neutral - or will be, by year 202X?
Small cores an also be leveraged as additional computing power for heavily multi-threaded applications; sure they're not as good as big cores but they are 1/4 the size and consume less power at 100%, so the perf/power and perf/area efficiencies are similar enough even in that worse case scenario.
It's only if you require a few highly performant cores (e.g. gaming or Photoshop) that the little cores are mostly useless, but even then they're only useless for that specific task - they can still take care of background tasks so that more of the big cores is left for the main task.
Even if gamers don't need small cores, and would gladly give them all away for just 1 more big core, the rest of the world disagrees.
The extra cache is jist a temp. measure. It cannotnbe a solution.
Well, more cache has been AMD's solution for the Ryzen 5000 series. It's mostly due to the 32MB L3 cache present on all models that even the Ryzen 5 5600X compares so well against the i9's in gaming.
As long as Intel doesn't pull ahead massively on frequency and/or IPC or add more cache to their midrange parts, AMD gets to reap the benefit.
I'd argue that large caches are here to stay. As computing gets faster and faster, the need to feed the cores (or GPU) with data increases as well. Even if memory or memory bus technologies provide the required bandwidth, latency will still be a problem, and cache is the solution.