Five to 10 years ago, when the future seemed to belong to electric cars - and California clean-air rules forced reluctant automakers to offer them - a small but enthusiastic group of optimists and environmentalists signed on as pioneers. While a few bought electrics outright, most signed leases that obliged them to return the vehicles after a few years. Regulators and auto manufacturers have since pinned their hopes on newer technologies, like hybrid gasoline-electric vehicles and, further in the future, hydrogen cars.