In 1963, almost every car manufactured in the U.S. had a solid rear axle. There were exceptions like the Corvette and Corvair. Today, many light- to medium-duty trucks still use live rear axles.
While the design differentials have changed, the ends of the axles have not. The improvements in have been made in the materials in the bearing, seals and grease. It is not uncommon for a vehicle to go its entire life on one set of bearings. But, failures due to impacts with curbs and loss of lubrication are not uncommon.
This article from the July, 1963 issue of BRAKE & FRONT END is one of the most complete articles on the subject, but it does need a few updates.