Ian Iveson" wrote in message
...

At the time of its introduction into audio systems, the main advantage of
solid state was convenience, surely?

Good question, because at the time of its introduction into audio systems,
SS wasn't all that convenient. The first SS power amps were fragile, and
some sounded bad all the time, others sounded bad with certain speakers.

Generally, changes have offered greater convenience or new features, with
acceptable quality.

No, better sound has always been the first priority for most audio
innovations. Sound quality in home systems as a rule improved steadily until
at least the mid-80s. Since then, most gains have related to video,
portability or over-all cost.

Recently, real gains have shifted to the area of convenient delivery of
recordings, audio or video.

Fidelity improves when a technology achieves commodity status, when all
examples become equally convenient or have the same features.

No, fidelity improves when a technology achieves commercial viability which
usually implies a large degree of practicality.