Radio had a huge development in the 1950's. It finally became truly portable. The portables in the 30's and 40's were mostly large, heavy, expensive, and with batteries that didn't last very long. In 1954, IDEA labs used a device called a transistor, to successfully replace vacuum tubes in a radio. They ultimately created a radio a little bit bigger than a deck of cards, that had good sensitivity and excellent battery life. 10 years earlier, that would've been unimaginable.
However, the Regency TR1 largely failed to sell due to it's high price and poor sound quality. Instead, much cheaper small tube portables became fairly popular, as did plastic table radios with crazy designs and bright colors.
Starting around 1955, other companies began introducing transistor radios. Zenith came out with their Royal 500 series, which performed and sounded better than the TR1. Many companies also made lunchbox sized transistor radios- these had the benefit of great battery life, but also better sound quality. Interestingly, while these were somewhat popular here, they were extremely popular in the UK.
The beginning of the end for the American radio industry was when the Japanese started introducing transistor radios at a much lower price. If a Zenith Royal 500 cost $75, Sony's TR63 was available for $39.95. Sure, it didn't sound as good and the build quality was not as good, but at almost half the price, it was good enough.
1959 Emerson 911