That’s a way of looking at it, though I’d tend to align myself with the Walkman here. Radio was still radio—just smaller. Once you could get the electronics for tape playback, then things started picking up.
Personal selection of music vs. portable music in general.
Earliest jukeboxes in bars had no amplifier and could only be heard by those around the horn.
There were portable turntables/victrolas for picnics and the like.
Amplifiers came along and so did transistors (which allowed smaller electronics). So something could make more noise without needing to be large.
The transistor radio was a breakthrough. To hopscotch through historical prescedence to 1970s or 1990s technology is the cliff notes version at its worst.