While I definitely agree with you on the whole, there are some specifics that are ignored by your comment.
The French Minitel system allowed for semi-free market activities, by allowing companies to use the system.
The German Bildschirmtext failed because it apparently kept too much control: the decoder boxes were expensive and only able to be purchased at one location, and I don't think they allowed for others to use the service.
Minitel was not something that had "never been built before", there were Videotex systems developed before. Of course, it's hard for a private company to use tax money to offer free terminals to everyone.
The French Minitel system allowed for semi-free market activities, by allowing companies to use the system.
The German Bildschirmtext failed because it apparently kept too much control: the decoder boxes were expensive and only able to be purchased at one location, and I don't think they allowed for others to use the service.