Goliath, meet David. Upstart Lyft might seem inconsequential in the face of Uber’s $62.5 billion valuation. But the ride-sharing giant’s seeking new management after a range of embarrassments, like endemic harassment complaints brought into focus by a recent internal investigation. Uber’s U.S. market share dropped from 84 to 77 percent in just five months, giving ground to its diminutive competitor. While investors fret that the bigger company “may be self-destructing,” don’t count them out: As a global leader, Uber’s entrenched network could put it back on Easy Street.