Efficiency in an EV is almost meaningless at the price level they're currently competing in. People who can spend 100k on a car from a brand-new brand will have a home with a garage or private driveway they can charge at. And buyers at that price have never really cared that much about efficiency.
Once again, if I were an investor, I'd want one of these executives to answer for their product timeline decisions. A fastback/coupe SUV should come after the more traditional SUV, if it even gets made at all. The Model Y could get away with the teardrop shape because it was the only midsize EV for a long time. Even the EVs released 5 or so years ago like the Mach-E, EV6, and Ioniq 5 weren't exactly traditionally shaped SUVs. Now with battery advances, we're seeing them with the iX3, EX60, and R2.
The two former vehicles have so many pre-orders in Europe alone that their factories have been running extra shifts. People who see the EX60 say they want the Cross Country variant even though it mostly has more black body cladding so it looks more "outdoorsy." The R2 has people like Doug Demuro saying that it is the EV he would buy. As annoying as some people might find him, I'd bet he knows more about the US car market than most people. On his podcast, he literally says that the Cosmos is another minivan that looks like a "weeny car" and it won't sell. This is backed up by the only influencer (Kyle from Out of Spec) that has seen and sat in the Cosmos says the R2 has more headroom in the rear seat. And his co-host on that episode found the exterior design interesting at best.
Selfishly, I want a more traditionally shaped SUV, with an 800v architecture if possible. Unselfishly, the market share of the fastback SUV is just multiple times smaller than the traditional one. Why would a company willingly target a smaller market? The US market has spoken. People here love things big and bold and brash. One of the worst on-road vehicles ever, the Jeep Wrangler, sells over 150k in the US alone mostly because it looks cool and rugged. The big three pickups (Plus Toyotas) get bigger and bigger with every generation.
If Lucid wants to zag, that's fine, but they might find out they're running into a brick wall with that more efficient shape.