Subsidiarity was accepted Church doctrine, and was never officially discarded by the Church.
Several Popes have spoken against Socialism.
Not so much, anymore, and it is a shame.
You seem to equate subsidiarity with a rejection of socialism. Certainly, socialism violates the principles of subsidiarity, but just bebcause it is doctrine that socialism is a grave evil does not mean that subsidiarity is Catholic doctrine.
Is there anyone you know of who has asserted subsidiarity is doctrine.
By the way, the Pope I first learned about subsidiarity through was John Paul II, but that was a rallying cry of Gdansk dock workers as a method of dealing with communist oppression; it’s nothing I understood the be Catholic doctrine. (I think it is universally applicable, as did Belloc and Chesterton; I just never got the sense that John Paul II ever meant to say, “Hey, America, you need to do this, also!”)