What infrastructure limitation primarily plagued early attempts to share digital audio?

Slow dial-up speeds making true, uninterrupted listening nearly impossible.

In the era preceding true streaming protocols, the major bottleneck preventing users from listening to audio or broadcasts in real-time was the inherent limitation of the existing network infrastructure. Specifically, slow dial-up speeds meant that transferring even moderately sized audio files took a significant amount of time. If a user attempted to play the file before the download was complete—even with progressive downloading—the connection speed often couldn't keep pace with playback demands, leading to frustrating interruptions, buffering, or an inability to start listening until the transfer finalized. The problem was fundamentally one of speed and consistency relative to playback timing requirements.