I think slides were still a thing through the 1990s at least among a certain subset of amateur photographers. Even Fox Mulder was always using slides in the X-Files.

My family never really had a slide projector. My grandparents must have at some point because the original reason I got a scanner that could handle slides was so I could scan some slides that came from them. I had a 110 camera when I was pretty young in the early 1980s. Later I had a cheap Canon point and shoot 35mm. I remember my parents had a camera that used disc film which wall the rage for about 5 minutes some time in the mid 1980s. It was really crappy film though.

I like film but digital is just so convenient. But like vinyl, I don't think film will ever go away completely though I don't see slide projectors making a comeback.