It's only recently when consumer software has become truly multithreaded. Historically there were major issues with that until very recently. Remember Bulldozer fiasco? They bet on the parallel execution more than Intel at the same time, e.g. same price Intel chip was 4 core, while AMD had 8 cores (consumer market). Single thread performance had been the deciding factor for decades. Even today AMDs outlier SKUs with a lot of cores and slightly lower frequencies (like 500 MHz lower or so) are not a topic of the day in any media or forum community. People talk about either top of the line SKU or something with low core count but clocking high enough to be reasonable for lighter use. Releasing low frequency high core count part for consumers would be greeted with questions, like "what for is this CPU?".

Are we just going to pretend that frequency = single-thread performance? I'm fine with making that replacement mentally, I just want to confirm we're all on the same page here.

>Releasing low frequency high core count part for consumers would be greeted with questions, like "what for is this CPU?".

It's for homelab and SOHO servers. It won't get the same attention as the sexy parts... because it's not a sexy part. It's something put in a box and stuff in a corner to chug away for ten years without looking at it again.

low frequency high core count part for consumers

That's not really what we're talking about. Apple's cores are faster yet lower clocked. (Not just faster per clock but absolutely faster.) So some people are wondering if Intel/AMD targeting 6 GHz actually reduced performance.

But the OS has been able to take advantage of it since mountain lion with grand central dispatch. I could be wrong with the code name. This makes doing parallel things very easy.

But most every OS can.