Unless I'm missing something, this isn't meant to replace the M-series CPUs Apple uses; the link states
"Qualcomm's Snapdragon X Elite CPU is designed purely for the Windows PC market where it will be competing against Intel & AMD while also tackling Apple's laptop portfolio based on their Arm chip architectures."
So, a competitor. If it's the bomb in the future, fairly sure Apple could adopt them;
It is a competitor with Apple in that macOS (as a whole) competes with Windows. Basically, when Apple gets up almost every fiscal quarter and says something to the effect of " 40-50% of new Mac users are former Windows users " . That kind of thing.
The meme has been for the last 2 years is that Apple is ripping huge chunks of market share away from Windows. The Qualcomm SoC would help with a 'stop loss' there. Mac products initially didn't see the post pandemic hardware bubble crash at first. "Apple walks on water .... M-series to infinity and beyond. Death of Windows coming soon... blah blah blah " . When it really just took longer to kick in for Apple. ( Mac sales tanking like everyone else last couple of Quarters. )
Not that Apple will adopt Qualcomm even if it does get better. They won't. The Elite X is build around the same UEFI boot system than Intel/AMD Windows boxes use. Apple tossed UEFI away with the Apple Silicon move. Direct official raw iron boot support is for macOS only. They added their own boot system ( based on iPhone). Apple has their own internal SSD controller. ( Elitie X doesn't). Added some corner case hardware to support Rosetta 2. Apple has their own GPU cores which they have spent lots of money on and are integral to the iPhone/iPad ecosystem that they are not going to walk away from at all. etc. Apple has done zero visible work to support 3rd party GPUs.
Apple set on fire and burn the bridge behind them on going back to using external SoCs.
This Elite X is far more about the "doom and gloom" folks have been throwing at Windows holding their market share, than anything Apple is going to do on hardware selection.
but given they're still semi-butthurt over having to use Qualcomm's modem chipset, I'd find it more likely they'd just update theirs to compete in speed/etc.
On the modem front, a pretty good chance it is about how Apple goes some proporietary integrate connector route for their modem versus some industry standard one for Qualcomm. ( Elite X using a M.2 slot that a variety of modems could slot into. ) Decent chance Apple will end up with something integrated onto the same package in some more pref/watt more efficient way.
Qualcomm is making rumbling noises that they intend to move custom Arm cores down to their mobile/phone SoCs also. The gap that the A-series enjoys would likely shrink. It isn't just a "mac" issue for Apple. Much of the noise here is that Qualcomm will keep a hold on the non-iPhone market also. Apple can't 'slow down and rest on laurels" on multiple fronts. [ And still quite far behind on modems. Not going to be 'cheap' to catch up there. ]