Once upon a time, the hit blockbuster films would make their network TV premiere about two, three, maybe four years later. Nowadays, they're all on cable (mostly TBS, FX, and/or TNT).
As for independent stations during the '80s: Some instances, a big movie would run past 10:00 pm and they would show it to conclusion followed by the news.
But in Britain (at least until 1999), ITV whenever they showed a big movie would have to break at 10:00 for News At Ten, followed by two minutes of weather, a five-minute late local news update, and then finally resuming the movie. When Five launched in 1997, they made a promise of not following ITV's lead when it comes to airing their films in primetime.
I wonder if CBC or CTV in Canada used to air movies that would cut into The National or CTV National News (unless if they edited it for time)...