I fly a Beechcraft 1900 D. The airplanes were built the same time as the 777, still with no autopilot. I think it has something to do with weight. I'm sure an autopilot would add almost 100 pounds to the empty weight of the aircraft. Most GA aircraft are better equipped than the Beech. No GPS, FMS, INS...just good old VOR/DME and ADF. Flying it keeps my basic skills up. It does have GPWS, TCAS, Radar Altimeter, WX Radar, EFIS, etc. No automation whatsoever.