Why did the camaro, charger, and mustang look similar then and now?
In the '60's and '70's, the Camaro and Mustang were "poor man's Corvettes", and in direct competition with each other. The Charger never looked like either of the others; it was larger, heavier, and more powerful. Chrysler came out with the Challenger in the '70's to compete with the Camaro and Mustang, and has done so again. Today's Charger is a family sedan.
Incidentally, I had a '67 Mustang coupe and traded it for a '70 Charger. Talk about a high-speed boat! The speedo had a 270-degree sweep, 0-160 mph speedo, and I had it all the way around to 0 many a time.
Yes the three look alike; however, have you noticed the European cars? They all look alike, too.