That does clarify the point, but I also don’t think that it’s true. It may well be that a major reason proposals for unified European rail never got off the ground before recently was that European countries rejected such proposals on grounds that it would make it easier for them to be invaded. But the rail systems in different European countries nonetheless developed independently, using different technology and standards, mostly (arguably) in the 19th century.

This complex process doesn’t reduce to 20th century FUBAR, even insofar as diplomatic and security considerations were involved in its evolution (and yet of course beginning in the 19th, not the 20th, century).