I flat out don't believe we have reached a fundamental perf/clock wall. I think the x86 vendors can do 50-60% better per clock with 2026 technologies. They are still infested with Netburst/Bulldozer ideologies. The reason is because they are both selling CPUs, and clockspeed still sells, even in supposedly all-ascended Anandtech Forum people.
Outside of forums like this nobody gives a sh-- about clock speed anymore. The days of marketing on clock rate when P4 was king are long gone. The average consumer has NO IDEA what clock speed a given CPU is, because it is all model numbers now and even if you dig for specs on a certain model you see a lot of hemming and hawwing about the actual clock speed since there's the default speed, the boost speed and then the extra special boost speed if you have really good cooling and there are asterisks about whether it is power limited or not and you have different boost speeds depending on how many cores are active. You think the average consumer could read that and mentally attach a single number to it?
Heck with the ridiculous profusion of SKUs most consumers couldn't even tell you what CPU is in their current PC beyond "Intel" or "AMD" (and I'm only about 70% confident they could name even that) Ask them if it is Zen 3 or Zen 4, or i5 or i7 and they've got no clue what you're even talking about.
Intel & AMD ship at the clock rates they do because that's what their designers believe deliver them the fastest CPUs. What Apple is doing is irrelevant - and Apple has been slowly catching up with clock rates so if that keeps up who knows they might be shipping at similar clock speeds by the end of the decade.