Besides how malicious it would be to use an M.2 physical connector for a non-M.2-compatible protocol, the pin count on the Apple connector is much higher for a

Besides how malicious it would be to use an M.2 physical connector for a non-M.2-compatible protocol, the pin count on the Apple connector is much higher for a reason. Adding a chip on to the SSD to mux between the different flash signals and retransmit them over a reduced number of high speed transceiver lanes would be cost-wise most of the way to putting a traditional PCIe controller on the SSD, without the benefits.