Why did Cardijn's writings go out of print?

Continuing on the theme of the literary eclipse of Cardijn, here is a list of the most recent published editions of Cardijn's writings that I have been able to locate:

French

Va libérer mon peuple! La pensée de Joseph Cardijn (Alex Ericx, ed.) Les Editions Ouvrières - Vie Ouvrière, Paris - Bruxelles, 1982, 359p. (Compilation of articles based on themes published for the centenary of Cardijn's birth in 1982.)

Cardijn face aux événements, 1950 - 1963, Cité nouvelle, Bruxelles, 1976. (Collection of newspaper articles.)

Laïcs en premières lignes, Editions universitaires - Vie Ouvrière, Paris - Bruxelles, 1963, 200p.

Dutch/Flemish

There was a Flemish edition of Cardijn face aux événements but I do not have the details at the moment.

Apart from that, the only Dutch/Flemish item that I can find for sale is: "Het zedelijk leven der jonge arbeiders op het werk", which was originally published in 1928.

English

Laymen into action, YCW, Melbourne 1964; Geoffrey Chapman, London, 1964, 175p.

The young worker faces life, Melbourne YCW, 1961, 60p.

Challenge to action, Geoffrey Chapman, London, 1955; Fides Publishers, Chicago, 1955, 148p.

Spanish

Laicos en primera linea, Nova Terra, Barcelona, 1965, 213p.

El joven trabajador y la joven trabajadora ante la vida, Comision Nacional JOC, Madrid, 1965, 134p.

La hora de la clase obrera, JOC, Madrid, 1965, 113p.

German

Laien im Apostolat, Butzon & Bercker, Kevelaer, 1964.

Das Apostolat der jungen Arbeiter, Quelle Verlag, 1962.

Mitten im Leben, CAJ/Deutschland/1957.

So it's pretty clear from the above that Cardijn's own writings stopped being published during the early 1960s. And it is true in each of the various languages.

Since his death, the only compilations of his writings published are Va libérer, which was put together by Alex Ericx for the Cardijn birth centenary in 1982, and the Cardijn face aux événements collection of newspaper articles.

The early 1960s date for when Cardijn went out of print is significant as it appears to correlate closely with the Ngraphs that I indicated earlier, which show how the number of literary references to Cardijn also plunges dramatically from that period.

http://cardijnresearch.blogspot.com/2013/12/cardijns-influence-as-tracked-in-google.html

http://cardijnresearch.blogspot.com/2013/12/the-literary-eclipse-of-cardijn.html

It makes perfect sense - no-one can cite Cardijn's writings if they don't have access to his writings.

But it leaves a major question that historians and future YCW generations will surely ask, namely why did Cardijn's writings go virtually out of print for 50 years following his death?