Used to be, a movie was rarely over two hours. This was from a lot of factors: shooting on 35mm, for one, was expensive. It was time-consuming to edit. Another, selling tickets at the cinema was very important. If you could keep every movie roughly the same length, then you’d be able to plug and play into most of the screens nationwide.
Now, most of our movie consumption is at home. Nearly all film and television production is digital. The turnaround from filming to distribution is shortened to mere months.
And thus, three-hour or longer movies are much more commonplace. Are they fun to see in the cinema? Well, sometimes. Though it’s much harder to hold off going to the restroom. And you almost certainly have as good a screen at home to watch it later. When it’s streaming.