Looking at older Revell kits such as the Lincoln Futura and '56 Cadillac Fleetwood, we see they both contained two figures:
It seems by the time the '58 SMP/AMT kits hit the shelves, figures had fallen out of favor and we were left with only the vehicles, and nobody to ride in them. Why did new kits no longer include figures? Is it because model kits were moving away from 1:48/O-scale and their association with model railroading? Maybe it was an extra cost/materials vs. value issue for AMT, Revell, etc.?