Thanks for sharing that, I learned something new today already :).
You can see the progression even over the last 10-20 years. We used to see the title of the movie, and then a few minutes of scenery with the actor's names on them. These days it's not uncommon for the movie to start almost immediately with the credits integrated into various background elements.
Yeah, as audiences' attention spans get ever shorter the pressure to GET ON WITH THE DAMN MOVIE gets ever higher, so filmmakers are always looking for ways to pare down the length of the opening credits or to present them in a way that also starts the story moving.
The same evolution has been underway for a couple of decades now with TV shows. Until the early 1990s it was commonplace for TV sitcoms to have a full opening credits reel, complete with a theme song just for that show. Think of the opening of Mary Tyler Moore [1] from back in the '70s, for instance, or Cheers [2] from the '80s; they both became iconic representations of those shows.
These intros helped set the tone of the show that followed them. But they generally took a full minute to run, and as the universe of options provided by cable expanded and remote controls became inexpensive, waiting that extra minute for the show to start began to turn off viewers. The push began to GET ON WITH THE DAMN SHOW, and so the traditional musical opening first shrank, then disappeared altogether. Today's openings run much shorter -- 25 seconds max -- and usually include just a couple of title cards and a musical snippet.
You can see the progression even over the last 10-20 years. We used to see the title of the movie, and then a few minutes of scenery with the actor's names on them. These days it's not uncommon for the movie to start almost immediately with the credits integrated into various background elements.