There is also a preference for TN-C grounding and a dislike of floating neutrals. So, in general hot+hot socket outlets are not allowed in modern building. Hence the demise of 127V
Not necessarily a contradiction - several German systems supplied a PEN along with the two or three phases of a 127/220V system which was solely used as a ground. Of course this only allowed/allows for TN-C-S and not TN-C (IMO about the most dangerous invention in the history of electricity).
I think mostly systems were standardized at 220/380V to allow for the use of standardized larger motors and other true 3 phase appliances in small workshops and other light commercial locations. Today, even many DIY appliances (garden mulchers, table saws,...) are available in more powerful 400V versions.
Switzerland seems to be the only country with ranges that use 400V elements connected phase to phase, more modern ones with a neutral supplied for control and lighting circuits. All others (except commercial models) are 230V only internally and can be used with any combination providing these. New ranges are supplied with a bunch of copper jumpers and the installer has to make sure they are connected to match the existing supply. These terminals are typically L1, L2, L3, N, N, PE and have to be jumpered according to the present supply. For example a 230/400V install would jumper terminals 4 and 5 and connect them to the neutral wire, the others to the corresponding phases. 230V single phase operation: jumper the aforementioned as well as 1, 2 and 3 connecting them to the phase wire, et cetera.
