The Echo was a budget level, sub compact car, which explains the size and cost difference to a great extent. Someone could certainly build a budget box hybrid, but few people in the developed world actually want an econobox with no frills. The Prius doesn't compete with bottom of the line Kia Rio's, it competes with mid to upper level Malibu's, Camry's and Fusion's. The Echo was a sales flop in the US in many ways. People didn't want another stripped down version of the Tercel. They wanted something with standard power seats, power windows, a decent stereo and room to actually fit 5 people. The Echo couldn't keep up with the Hyundai's because the Koreans offered standard options on small cars what was once only available on big cars. Toyota has always been crap about standard options. Finally, what evidence do you have for "uses less natural resources"? Oil production and transportation is very resource use heavy. Combustion engines are very inefficient--losing gobs of energy to heat loss, complicated transmissions and the like.