.
The “spirit of VII days” habit of placing the tabernacle in side areas was to allow space for adoration and private devotions outside of Mass. There was nothing diabolical about it.
In the years after V2, it was felt that, OF COURSE, all Catholics are very aware of the Real Presence. But some claimed Catholics were ignorant of God’s Presence in the Word. So some parishes moved the Blessed Sacrament to one side of the altar, with the Lectionary on the other side of the altar,
equally prominent. Remember this was when “equality” was a mantra. Some parishes even had vigil lights in front of the Lectionary.
From there, it was an easier step to move the Blessed Sacrament to an adjoining room. Often this change was lumped together in a larger project: “We need to clean the Church, repaint, and, um. other updates”. Usually they find the new décor doesn’t have room for a prominent crucifix either. In one parish they decided to start an Adoration Chapel. Great idea! But when people found the Blessed Sacrament in the chapel, they noticed no provision was made for the Blessed Sacrament in the Church. As time went on, fewer people went to the Adoration Chapel, so it is open very, very few hours now. But the Blessed Sacrament was never put back in the Church.
The 1960s assumption - that Catholics overwhelmingly understand and believe in the Real Presence - no longer holds. Catholics who go to separate adoration chapels, which are good in themselves, were raised in churches where the Blessed Sacrament and crucifix were prominent in the church itself.
Historically for most Catholics, the main adoration of the Blessed Sacrament is in the church, before and after Mass, or other activities - even if only 10 seconds recognition. All the other adoration - including now the adoration chapels, are a great supplement for relatively few; not a replacement, for the great majority of Catholics.