You can imagine how desparate Microsoft was to finally get the Windows on ARM thing going. They really needed a vendor to focus up to deliver a proper ARM experience. Unfortunately, from what I've read, there is still no real reason to use Windows on ARM devices. Apple is a completely different company. They vertically integrate a lot more while Microsoft always has a network of partners in whatever they do. And it makes sense to me because they are present in so many more industries and have way more products so doing each one completely vertically is way more risks. Microsoft just want a piece of every pie. Apple on the other hand always has a few golden apples which they sell with high Apple tax and have to make sure they execute perfectly. Windows on ARM is a defensive move from Microsoft to have insurance from x86 falling behind, while Apple on ARM was an attempt to do better than Intel can
Apple and ARM got together in the period of Apple's CSO who knew a thing or two. The Qualcomm/Microsoft claims to a monopoly business deal will have to stand before a disinterested court of justice to be decided years and years down the road. By then it won't matter.