In this articleRIVNBrand new Lucid electric cars sit parked in front of a Lucid Studio showroom in San Francisco on May 24, 2024.Justin Sullivan | Getty ImagesDETROIT — Challenges are mounting for all-electric vehicle manufacturers Rivian Automotive and Lucid Group as the companies try to sell investors on a brighter, more profitable future to come.But things could get worse before they get better as both automakers are set to report third-quarter results this week, starting with Rivian after the bell Tuesd ...