Couldn't they have gotten the performance for gaming without the complexity of more threads and reduced cost even more?
E-cores are cheap.
Really cheap, as they're essentially re-worked, stripped-down Skylake cores. They lack HT which was one of the main sources of security issues for Skylake.
And for Raptor Lake, over Alder Lake before, the E-cores run a bit faster, have lower latency, and do not inhibit ring clock speed - which results in higher overall memory bandwidth and lower memory access latency for every core.
So those eight E-cores on the 13600K and 13700K are extremely helpful. They still have full-fat FPUs and so on, so you could think of them as being something like having a whole 9700K (at 10nm / Intel 7) bolted on to the side of the six or eight P-cores in these CPUs. They can handle any work assigned to them.
IF you need high core count systems are you really gonna 'save' the 50-100 bucks and not just get the higher end part?
For the 13600K, you probably should stretch to the 13700K for the additional two P-cores. But just for gaming? Hard to make that argument depending on what other budget considerations are at hand.
Couldn't they have gotten the performance for gaming without the complexity of more threads and reduced cost even more? Even if only cost internally for the product stack?
I guess this depends on the comparison. There's a lot of elegance to be found in AMD's more traditional approach, but for those that do
more with their systems than just gaming - and by more I mean they have all the stuff running that a desktop user and a gamer would have in the background - Intel's approach makes sense. The P-cores can handle the demanding gaming threads, the E-cores can handle everything else - effortlessly.
Hard to measure and hard to reproduce I know, as no reviewer would purposefully use such a methodology on a product launch review, let alone variability with all the additional variables and likely run-to-run variance casting doubt on the results. This is just how I look at it.
I think, as you move down the stack - it's all about salvage bins and strategically pricing/marketing them. Not that these were specifically created for this mid-market segment.
As long as Intel has been doing these bins, I expect they very much planned things this way. Intel needed to both head off AMD's gains with Zen 4 as well as provide an uplift in comparison to Alder Lake, thus providing a motive for folks with anything older to jump in this round.
Strong gaming performance, strong MT performance, and available inexpensive boards and support for less expensive DDR4 with Raptor Lake all put Intel pretty substantially in the value leader slot.
They are "Efficient" at consuming power..
Zen 4 is leading in perf/watt at the very highest loads, but average loads are surprisingly 'normal' for both of them. For gaming and general desktop use, outside of say 3D rendering, both ecosystems are more or less equivalent.
