I somehow doubt that it really changed that much. People have been quite affectionate with cats for a long time. Though we still have a very wide range of relationships with cats from affectionate to basically wild animals people feed.
Ex: Francesco Bachiacca | Portrait of a young lady holding a cat, 1525-30
Cave's role was just bizarre. As the movie starts you hear an Australian voice reading out a letter, so I wondered who the Australian connection in Wain's life was. Then much later you see Nick Cave reading out the letter, looking and sounding like Nick Cave, but evidently supposed to be HG Wells. Very weird casting, even in a movie mostly about madness. It just didn't work at all, I thought. That was the one thing in the movie that stuck out as strange/bad. I've no idea what they were thinking.
The Electrical Life of Louis Wain (2021) https://www.imdb.com/title/tt10687506/