Yeah because modern filmmakers make it very hard to hear dialogs for some reason and actors are encouraged to mumble. If I remember correctly even Nolan admitted it.
And they often speak very quickly--I often rewind to catch critical plot points. It's a lot different from a stage play, where actors enunciate so clearly. (Not that I want stage cadence and booming voices from a film ... they are different art forms.)
Also I watch of English language material that uses accents quite different from what my ears are tuned to.
People watch Netflix to switch their brain off - having the text there helps along with the visual and sound to deliver the content. However, text is inferior to both visual and sound as a delivery mechanism.
Subtitles increase the signal to noise ratio. At least in our house. We have to keep the tv low to not wake the child. A volume of 10 with subtitles is similar to volume at 16 without subtitles.