Why are so many automakers, tech firms, components suppliers and ride-hailing companies pouring billions of dollars into developing self-driving cars and trucks? In part, it’s because the payoff could eventually be worth $7 trillion. That’s the estimate of a new study from the research firm Strategy Analytics and Intel, one of several tech giants investing heavily in autonomous-drive systems. “This technology is driving big changes,” said Kathy Winter, vice president and general manager of Intel’s