Unless I'm missing something: Huh? Apple is just using regular NVMe/M.2 SSDs, nothing special about them. Lots of laptops have the option for M.2 NVMe SSDs, and most newer desktop motherboards have the slot for it.
It's also not uncommon in the "lower ranks". I just bought a 800 € ultrabook with a 256 GB Samsung PM961 SSD (NVMe, 2.8 / 1.1 GB/s) and the Skylake i7 for example.