Hardly anyone used it because it was barely available on a single brick of a "phone" from HP, with a price only a corporation would consider.

As for the motorola attempt, it needed two plugs (hdmi and USB), and they could never commit to having a single spacing and overall phone shape across generations. End result, each phone needed its own docks until Motorola went "fuck this" and released a lapdock with some massive cables instead of the dock plugs.

And the Samsung attempt seems poised to develop the same problem...