Naturally we will come to the limit of hard drive technology which is still moving forward and should be for the near future. But for the next generation of gadgets, it seems only logical to take up solid state memory for they consume less power, have no moving parts and are becoming cheaper year after year.
Other applications of sata hard drives are slowly being replaced by memory sticks in the GB range and only time will tell when the two would catch up. For the PC market however, sata remains as USB 3.0 goes mainstream with bigger capacity and faster access times.