There were a small number of difficult Captains. Always were. Always will be. Cabin crew thought they were unreasonable towards them. They were right - but these Captains were unreasonable towards everyone....! They were not the norm (but they were a pain).
The physical separation of flight crew and cabin crew (upstairs/downstairs) and the fact that the first B747s suffered frequent engine failures which made the Captains understandably reluctant to leave the flight deck to tour the cabin as they used to, left a bit of a power vacuum in the cabin which the new Cabin Service Officers were happy to fill.
From the other side, the large cabin crew and increased complexity of cabin service needed a new kind of leadership which the CSOs quickly developed. I thought the cabin service adapted quickly and well to the new space and most CSOs did an extremely good job on board.
The problem was a (small) number decided that they now (as Officers with four thin rings on their sleeves) were in charge of the whole aircraft and stopped liasing effectively with the Captain and flight crew, some even encouraging the rest of the cabin crew to do likewise.
The company was beginning to discover customer service and Cabin Crew as a department moved from Operations to Commercial, separating them further from flight crew.
In short, change was needed but badly managed - as indeed was the whole of the new British Airways following the merger. But that's another story.