I am not sure how relevant Intel/AMD and Apple Silicon are going to be to each other considering the former eventually cannot run macOS and the latter eventually cannot run (x86) Windows.
That doesn't make much sense in the context of Apple taking more market share. If the laptops are not taking it from Windows systems where are they taking the share from.... mac Desktops , iPads ?
The probably with this position is that even Apple doesn't believe it. For many years Apple ran a "mac vs PC" commercial. Now they don't directly talk about it but it often implied. When Apple says they have better Privacy it is not Mac more private than the iPhone or iPad. They are talking about those other folks with broadly substitutable goods. No, Apple doesn't have completely transparently swappable substitutes, but they do complete.
Second, at least once a year Apple will mention in their quarterly call about how the iPhone/Mac are doing that they are getting XX% of switchers. If these goods being switched from are not competitors why call it a 'switch'. Those folks are switching substitutable goods. And Apple basically relies on that for growth. There have been years where the overall PC market units number are down and Apple is slightly up or flat. Most of that comes from rearranging the deck chairs on the same boat. Apple peeled out more folks from Windows than Windows peeled out from Apple. Even more apparent when look at USA vs Worldwide market share. Once loop in numbers where Macs are relatively less affordable their market share drops.
Appel could grow share if they were bring loads of "new" folks to the worldwide PC market. They wouldn't have to lean so heavily on getting "swapper" if they could get folks who were new. That is another stat where Apple does some tap dancing. They have "bought my first computer" stats. but likely if you cut out "bought my new computer with student loan, got it as a gift for school , etc. " that not really seeing substantial system unit growth in areas where Windows doesn't also have units. Parts , repairability , etc all matter more where there is no local certified repair shop primarily because the regional median income is relatively low.
As Jobs said decades ago the PC wars are over. Apple's main objective is to prune off profitable customers and dump the ones that are not (for Apple). That is a move where they build fewer , more focused products. The net impact of that is that their market share growth potential is relatively limited. Steady independent single digit growth (i.e. gap from overall PC market ) pulling off relatively small number of switches at higher than industry profits. Minus Windows and the top 4 PC system vendors shooting themselves in the foot multiple years in a row, there is probably not a huge share win for Apple. With all the more antitrust scrutiny going around ; nor do they really want that.
So people will make their architecture decisions based on the OS, not the processor, and if you want/need both macOS and Windows support, you will have dedicated machines for each platform.
It is higher than that. If folks can get the apps they are comfortable with then Mac/Windows are more substitutable goods. The actual operating system (not the Finder / Window / GUI manager ) that is not a rigid barrier for most.
The other fallacy is that Windows is 'suck' solely with x86_64 and it isn't. What matters to folks is can they run their apps. That's why Apple has Rosetta. Also why Microsoft has a basic equivalent on Windows on Arm. If Adobe , Microsoft , Google , Blackmagic , and Avid woke up tomorrow and decided that macOS was a waste of time and left, then macOS would be in trouble. Not having the major league apps is part of what keeps Linux in the minor leagues in desktop OS percentage.