In 2021 Intel will roll out Adler Lake ( probably gen12 ) CPU SoC with 4-8 big cores and 4-8 smaller cores. If they get the right updates weaved into Windows to do effective load balancing out of the small cores when the workload is low then that should substantively shrink the battery life gap substantially.
Technology Vision
adoredtv.com
Light workloads , the target Adler lake goal can cut a Gen 11 (tigher Lake) consumption almost in half (40-50% range in some cases ). Chop down the video decode/encode and Zoom calls get longer without big primary processor cores being much different.
( Intel could pull it off since a major portion here is software and getting cooperation from Microsoft.... which has Intel SurfaceBooks. It isn't solely based on fab tech that is stuck. ) Are they going to match M1 (and M1-variants coming later in the year)? Probably not but all Intel has to do shrink the gap enough and point to "continuity" of the software stack for end users to retain a large fraction of the users. Most users aren't upgrading ( most users are generally on much longer upgrade cycles now so that also blunts the short term impact M1 Macs will have. )
It isn't a slam dunk for ARM. Pretty likely there will be come Cortex-X derivaties show up, but the C8X solutions now just aren't competitive if needs substantive "horsepower". Yeah get longer battery but somewhat "slow".
The other ARM implementations will have to deliver for ARM to go mainstream. So far that isn't happening. Qualcomm is dabbling at it, but not in with boot feet and full effort. Cortex-X1 will likely be better but still ( and a door that Microsoft could go through directly themselves ... pragmatically get a custom solution from ARM instead of Qualcomm. ) .