They mean behind fixing the bugs intel et al introduced into their silicon to cut corners in pursuit of higher performance? Yes, that's a reason...
I also always wonder what they are doing at phoronix to always get such weird "results", also they still don't seem to have understood what -RELEASE and -CURRENT are and bragging about what brand-new hardware isn't supported in RELEASE.
Also my Alder Lake laptop booted up just fine with 13.1-RELEASE and I only used 13.2-beta (meanwhile upgraded to R2) to set it up to get/test i915 driver support for the integrated GPU (works, but graphics output on XFCE freezes after a while so I'm using the modesetting driver for now) and the updated AX211 driver (seems to work, but I'm always using wired LAN anyways...).
True, linux supports almost every new and exotic hardware shortly after release - but usually a lot of those initial drivers are garbage and far from something you could consider 'production ready'. Something like that doesn't belong in any -RELEASE. I'd rather wait a few weeks/months to get something that actually works than having to deal with kernel panics, firmware lockups and other annoyances. If I'm ok whit those possible problems and absolutely *want* some new hardware fully supported, I'd just go for CURRENT.
And about the P- and E-Cores: I couldn't care less. that CPU (i71255U) uses ~4W during normal workloads, so I highly doubt there is that much to gain to justify making working on that a priority.