Silent movies had live music playing from start to finish.
When sound was developed for films, the composers were mostly classically trained professionals who wrote whole soundscapes that were nearly continuous throughout the films. Go back and watch a film from the 1940s or 1950s and listen to the scores. Many of them are magnificent compositions!
Later film scores began to incorporate famous songs to set the period or tone of the story and the original recordings were licensed for use in the film.
Today, I think the problem youre experiencing is the sensory overload that seems to permeate our society. People seem to need constant external stimulation. Look at how people are fixated by their smart phones! They surf the web while listening to music or podcasts through their ear buds. I dont know how to split my focus this way. .
Movies are an extension of this behavior in that the soundtracks, special audio effects and other audible elements are cranked up to 11, (if you get the Spinal Tap reference!). If the sound isnt loud with an extended frequency range (sub-woofers, anyone?) and volume that will leave your ears ringing then the film wont measure up to the public.
Ill end by agreeing with the poster above who wrote that a loud soundtrack distracts the audience from the fact that the film sucks!