I wonder why Apple would even want to protect a battery charger IC? All of the interesting stuff would be in software anyway. Maybe the reason repair shops can’t buy it is more mundane. Basically it’s an expensive part, particularly to Apple’s logic board, and distributors don’t believe there are enough Rossmanns out there to sell through a 100k part factory order. When I made PCBs for a large company I had parts I could buy direct from Maxim, at 250k parts minimum, that weren’t on Digi-Key for just that reason.