Knowing Apple had Intel Macs running in the background for years before they announced the jump to x86, I wouldn't be surprised if they already have the chips and know how well it performs.
And I also wouldn't mind if they did another demo like they used to: https://youtu.be/oxwmF0OJ0vg?t=24m45s
The Intel chip you mention isn't in any Apple machine at all. (Except maybe the iMac Pro? Is it even in that?) So you be real. I don't think you've actually looked at the benchmarks. You should do so. I think you'll be shocked at just how much overlap there is, just like I was.
What benchmarks? Geekbench? That's the only one I've ever seen where the fight is close, and Geekbench (like everything that boils performance down to one number) is nearly completely useless.
If you see a two-watt phone CPU beating a 45-watt actively-cooled laptop CPU, you can either conclude that the phone is alien technology decades ahead of anything else on the market or that the benchmark is broken. Which is more likely?
https://www.realworldtech.com/forum/?threadid=136526&curpost...
Geekbench may not be the best tool for determining the power of a processor, but at the least it gives you a general idea of power across devices in a consistent set of tests, which can be extrapolated.
That post is pretty outdated. It's about old hardware and an old version of Geekbench. But people still use Geekbench 3 and old x86 hardware, so it's not totally irrelevant.