Very good summary from another Apple survivor! One point to add. Conventional wisdom would answer your last question with an Apple or Google response. Not so quick.
Apple makes money on hardware, a nearly unique situation in the computer/mobile device world. In fact, they MINT money in hardware and control over 90% of the gross margin there. Closer to 100% when Samsung has a problem or recall.
Google makes money on ads/search. They wisely sat on the sidelines and let the hardware vendors beat each other to death on margin. As the dust settles, it was clear to Google that the falling quality and support of Android phones was a drag on their image, so they are back in the hardware business. Not a problem, they can ship lots of dollar bills with each Google phone and still make money on everything else.
Apple buyers pay for support and quality, Android users pick the level of price/performance/quality that matches their need.
The bigger question is this. Who can compete with either? In the first world, no one. In China or India, cheap knockoffs for quite a while. But, as users become a bit more sophisticated, they will demand style, quality, image, or other attributes that US$100 Androids cannot supply. Then, Google and Apple step in.
While all of this does not affect MSFT now, it does mean they are no longer on the top of mind for the next generation of device buyers. My kids’ high school issues a Chromebook to every student. Their colleges looked like an Apple commercial. Logos everywhere. Users do not see if apps use AWS or Azure. Only Office or the startup logo on a school lab computer reminds them of Microsoft.
Next generation will be very familiar with Apple logo or the little Google guy. They may wonder what the four color flag is that is on that ancient device their father uses to read the news.