They are no black magic. ARM is simply better optimized for mobile devices and Apple being a walled garden with tightly controlled hardware and software, they had the ability to transition into ARM chis on laptops without much hassle. However ARM chips do suffer in performance and some other areas. That said, the rest of the gang is following up with this move. Won't be too long before they lose even that advantage.

Also, I wouldn't really call them a game changer. I understand what you meant by your statement, but as a laptop MacBooks are a really bad choice with almost zero repairability these days. From glued batteries, soldered memory to programmed chips which stop working if you move them to another board. All of this (and much more) combined with their repeated engineering failures with even simplest of things makes them extremely undesirable in my eyes. Problem is, people never realize there's a problem until warranty program runs out and devices start massively dying. Those that do survive are touted as "Apple quality", but millions of others remain forgotten.