If global automakers think they can extend their dominance in China into the electric era, they may be in for a shock.

Kings of the combustion age such as General Motors and Volkswagen are falling behind local players in the booming electric vehicle market in China, a country that's key to funding and developing their electric and autonomous ambitions.

For Beijing office worker Tianna Cheng, the main dilemma when she was buying a 180,000 yuan ($27,000) Xpeng electric crossover was whether she should go for a BYD car instead or a Nio; she did not seriously consider overseas marques.