>It seems to me like they voluntarily focused on power consumption over performance. It's a valid choice but it wasn't forced on them, and raw performance is more important for desktop

Because people wanted thinner and lighter laptops.
The Kabbylake-R "8th gen" mobile CPUs are absolutly amazing, 4 cores at over 3ghz with 15W TDP is absolutly bonkers: https://ark.intel.com/products/124967/Intel-Core-i5-8250U-Pr...

It's also important to state that it's not like AMD did anything better.
Zen is a very attractive architecture but IPC wise it's slightly behind at about the same power envelope as Intel (both AMD and Intel measure TDP differently but the power consumption of the CPU per core is more or less identical for the same frequency (with intel slightly lower still) for non AVX loads).

Laptop sale outnumber desktop sales, and it's not like high end consumer and enthusiast CPUs for the desktop are that power conservative cooling 100-200W of TDP isn't easy even with water, I'm running a full custom loop on all my computers and cooling is still a problem when reaching high clocks at full stress.

So while Intel could've pushed Coffee Lake 1-2 years earlier with some sacrifice (especially in profit margins) as far as IPC improvements I really doubt they had any choice even if they would crank their CPUs a notch or two when power consumption goes the best the would've gotten is slightly higher clocks.

As far as the core count goes, yes Intel was lazy, but for AMD that was literally the only option a 4 core Ryzen wouldn't interest anyone since AMD can't get their process above 4.0ghz reliably even on low core count CPUs, on the IPC front it's behind, branch prediction is still quite behind Intel (one of the reasons why SMT give slightly higher relative advantage on AMD CPUs is all them stalls).

AMD has been operating at a near constant operational loss for the past 4-5 years, their only profitable quarters were when the console revenue cheque came in and in the past 4-5 years they maybe had 2, they had to pay MSFT back a truck of money because GloFo cocked up their 20nm process which caused Xbox One S to be delayed and had to cancel Skybridge and a few other projects.
Intel has been rocking on at near 60% gross margins for years now, and while it's easy to paint them greedy if I was a corporation I wouldn't likely do anything differently.

The 8th gen is quite a big deal when it comes to Intel vs AMD more that some people would care to admit.
Intel has a the fastest 6 core CPU out there with a built in GPU, it managed to squeeze 4 cores into a 15W part on the mobile side, this time around both mobile i5's and i7's will come with 4 cores no more 2 core CPUs for the mainstream and these are the U parts the ones that were traditionally dual core even for i7's, the HQ parts will likely bring 6 cores to mobile and with 9th gen CPUs launching for the ultra low voltage platform later this year AMD will have even more of an uphill battle where it counts laptops and other mobile devices.
AMD needs to have a viable product for the mobile market, and with raven ridge coming for mobile this year they can only pull 4 cores with their APUs and how power efficient is it going to be no one still knows.