anyone know why they never took off? (pun intended)
would be interesting to know what stopped the turbine from becoming a mass production engine.
Up and into the 1950s, consumers wanted vehicles to last longer and require less maintenance. Automakers were figuring out how to make the bodies last for more years/miles, but not so much the engines. They extrapolated that this trend would continue indefinitely (it didn't), and a new powerplant would be required with more longevity than internal combustion engine. That was the incentive for automakers to explore the turbine as an alternative.
All of the big-3 plus at least one British automaker developed turbine-powered prototypes. Chrysler developed and patented some innovations which simplified adapting a turbine to automotive use, including the regenerator and method to connect the output to their existing 727 automatic. This gave Chrysler an edge.
They found during the field testing that gasoline was not a good fuel choice, because the additives in the gas (including lead) would coat the turbine blades. Chrysler recommended fueling with diesel or kerosene. Not a big deal today when many gas stations have a diesel pump, but it wasn't easy to find in the 60's except at truck stops. That was an inconvenience for consumers participating in the Turbine trials.
The field testing of the 1963 Ghia Turbines ended when the EPA came out with their new emissions standards, which their existing turbine engines could not meet. However, development of the turbine engine continued in the lab at Chrysler, and they almost green-lighted production of a 4th gen turbine engine in the late 70's, which was able to meet the latest emissions standards.
The final decision came down to Iaccoca, who said no. As
@Davea Lux said, the turbine was still expensive to produce, it was unknown how much costs could be reduced through mass-production economies of scale, and the company wasn't in good financial health at the time to take such a gamble. Also, IC engine technology had continued to increase the longevity of conventional IC engines, and many first-owners were now trading in their cars before they were worn out, indicating that vehicle longevity was no longer such a consideration when purchasing a new car.
Cool as the idea of the turbine is, this was probably the best decision. The turbine engine probably would have been relegated to a niche market, much like diesel-powered cars did later, at least in North America.