In the industry, some suspect that G.M. and the Obama administration decided against selling the Volt at a loss because they want the company to appear profitable before its long-awaited initial stock offering, which is likely to take place next month. For taxpayers, that approach might have made sense if the government planned on selling its entire 61 percent stake in G.M. But the administration has said it will sell only enough equity in the public offering to relinquish its controlling stake in G.M. Thus the government will remain exposed to the company’s (and the Volt’s) long-term fate.

So the future of General Motors (and the $50 billion taxpayer investment in it) now depends on a vehicle that costs $41,000 but offers the performance and interior space of a $15,000 economy car. The company is moving forward on a second generation of Volts aimed at eliminating the initial model’s considerable shortcomings. (In truth, the first-generation Volt was as good as written off inside G.M., which decided to cut its 2011 production volume to a mere 10,000 units rather than the initial plan for 60,000.) Yet G.M. seemingly has no plan for turning its low-volume “eco-flagship” into a mass-market icon like the Prius.