Simeon said:
After Weimar all germans were equal in the eyes of the law. If Johannes had left his fortune in state (without a will) it probably would have had no choice but to follow partible inheritance (I do not know for a fact if germany does follow this system if someone dies in state).
I think you mean "intestate", not in state. The TnT fortune is tied up in trusts and agreements that likely predate Johannes' passing (and inheritance, for that matter). If the estate is entailed to the next head of the house, it wouldn't matter whether Johannes had a will or not.
Or personally, if I had no son I would find it hard to pass a huge inheritance on to a "distant stranger" to follow tradition of an instrument of government that had lapsed 100 years ago rather than my daughters. An explaination or reference of why german nobility follows this practice, or if they have been granted some special dispensation from the republic would be appreciated. Maybe it is just tradition, suprised no one has broke with it though.
It is tradition, and most, if not all, the German families have entailed their assets, or placed them in a trust for the use of the head of the house. Johannes probably couldn't have handed it to his daughters without facing angry relatives. And there's an understanding that the head of the house should be able to live as the head of the house. Running the large estates, managing the castles, etc, is a time-consuming job, which is why you see some instances of elder sons resigning their rights to the headship in favor of younger sons who are willing to do the job.
Also, along the same thought, the princess/prince title. Why are they "entitled to use the title" was that part of being mediatized? Is there some instrument that allows them to from the government?
Germany, unlike Austria, allowed titles to be made into surnames. Germany allows royals to change their surnames as their titles change. For example, in Germany, an Erbprinz (Hereditary Prince) would be allowed to change his name to Herzog (Duke, and presumably head of the house), once he inherited. In Austria, however, the surname-title wouldn't exist at all (Archduke Otto of Austria is simply Otto Habsburg), and no name changes would be allowed, or would be very difficult.