Blu-ray, we hardly knew ye. Consumers are starting to buy video players for high-definition Blu-ray discs, and sales are expected to rise sharply in the next few years. But already some of the technology’s backers say its days are numbered. “I think it has five years left,” Andy Griffiths, a director of consumer electronics at Samsung, the second-biggest seller of Blu-ray players, told the media this month.