When did cinemas stop having sing-alongs?

There was one in my town not to long before COVID to Sound of Music but, again, this is not what the OP is asking about.

There used to be shorts prior to the movie that were singalongs to well known popular music. I’m 60 and I don’t recall ever seeing one.

My earliest memories of going to a movie theater would have been the early 70s and I don’t recall ever seeing a movie or a cartoon prior to the main feature except when it was a theater showing a vintage film and they’d do an old timey cartoon and news reel as part of the schtick.

My memories are similar - the first movie I actually remember seeing was in 1975 and there was no sing a long , no cartoon and of course no newsreel. That was coincidentally or not , the first movie I saw with my friends, not my family and also the first PG movie. If the Walt Disney type G movies I saw before 1975 had cartoons or sing-alongs , I don’t remember them.

My mother recalled national anthem(s) being played/sung before/after movies in Canada and the UK during WW2.

I remember the National Anthem being played at the end of the night in cinemas in the UK in the 70s. No sing-alongs though, except in Pantos.

I don’t remember one in the theater. I’m sure my parents took me to see Disney’s re-releases of Pinocchio and Snow White, etc., but I have no memories of attending. My earliest theater memories are “The Ten Commandments” and “The King And I”, and understandably there was no cartoon.

I went to Saturday kids matinees weekly in the early 1960’s and I don’t remember any singalongs. There were the occasional cartoons before the feature, usually Bugs and other WB characters. I suppose by then, most houses had those newfangled gramaphones, so a public venue to hear recorded music was not such a big deal.

I suppose TV cartoon shows (Bug Bunny Road Runner Hour, etc.) probably eventually killed the cinema cartoons, and the studios stopped making many new ones.