General Motors Co. said the robotaxi service it is developing could potentially eclipse the profits it earns in the core automotive business within a decade, an ambitious target based on the company's strategy of lowering its reliance on manufacturing by providing high-margin services. GM executives, speaking at an investor conference Thursday, said the company aims to run a large-scale fleet of driverless cars in big cities by 2019. GM is among the first major driverless-car developers to attach a timeline to the commercialization of autonomous vehicles, and the 109-year-old auto maker is racing big tech companies and Silicon Valley startups to lead the reinvention of the way people own and operate cars. GM last year earned about a profit margin of 7.5% on its $166 billion in annual revenue from global car sales. Chief Financial Officer Chuck Stevens said that the company believes a driverless-car service by 2025 will offer 20% to 30% margins and a "total addressable market of several hundreds of billions of dollars."