This actually makes me feel better haha. I always felt thay my English is STILL not good enough, even after 5 years of living in an English speaking country, to fully understand dialogue on screen.
Add to that lazy directors/creators who think they can fix it all in post, and classist ones who think if it sounds good on their super expensive equipment it doesn't matter what the average person has available.
Similar things happen with visuals, that's partly why you get over use of dodgy CGI and overly dark scenes.
As for me I use subtitles because I live under a flight path across the road from a mechanic. It's either that or rewind every ten minutes.