I don't blame the manufacturers. In the early to mid 2000's manufacturers were turning out radios (especially clock radios and kitchen radios) with MP3 player docks, especially IPod docks. I have a Sony alarm-clock / boombox / IPod player (with HD radio capability) within reach. I don't know how many of them sold, comparatively, but the fact that they aren't plentiful in homes speaks loads. By the time this Sony was produced, flip phones were gaining more capabilities, IPods were so portable people could carry them everywhere, and the smartphone was already in development or production.
A few years later, radio manufacturers turned out radios with AM/FM and bluetooth. But by then the die had been cast.
The phone took over because it was convenient. On that side of the issue, we are in complete agreement.
You can make all sorts of cool equipment and additions and modifications to a medium, but that doesn't mean the public won't ditch it for something else that -- as you mentioned -- does much of the same thing (in this case, music delivery and information access). And when people adopted the smartphone especially, they always took it with them wherever they went. No other device necessary.
