I really hope Apple doesn’t get credit for “inventing” something that existed already on that one. Hybrid hard drives/intelligent caching have existed in a lot of forms on PC’s for a few years now. The drive automatically caches data to the SSD and when it runs out of space, dumps the least used data to the HDD.
Lots of motherboards now even include a dedicated mini PCI-Express SSD slot directly on the board to eliminate the bandwidth bottlenecks associated with a SATA drive.