Concept cars often having been run through either CFD or a wind tunnel and also haven’t been vetted for NHTSA requirements, and both those and coefficient of friction are why cars all start to look alike.
I can’t recall the vehicle now but there was a futuristic car around the turn of the century that had a lot of buzz, but changed dramatically for production and nobody liked it. But an engineer on the project said the concept car had less aerodynamic drag going backward than forward, which is quite an achievement.
That is one of at least a dozen experiences I have had that tell me not to get attached until the prototypes ship to car reviewers for examination.
The Mercedes W124 had a cfd of 0.29. It doesn't look anything like modern cars with similar cfd. (VW Arteon, Volvo S60, Lexus IS)
The one I remember is the Pontiac Aztek.