Wall Street has long taken a dim view of legacy automakers — but that’s begun to change as the likes of Ford Motor Co. and General Motors Co. demonstrate they’re serious contenders in the electric and digital revolution that’s reshaping the automotive industry. This reassessment is happening even as investors appear to be cooling on many of the pure-play electric-vehicle startups that had been richly valued by financial markets seeking the next Tesla Inc. Some of them are now struggling with leadership shakeups, federal investigations, challenges ramping up production amid unprecedented supply…