I think teens and young adults who still live at home are today's primary theater-goers, along with dads of small children. That's why there's so many comic book films.
Today's increasingly affordable massive 4K home theater systems have far eclipsed the visual and audio quality of the cinema. For many, it's preferable to view at home.
Also, apparently the movie theaters don't make any money from the ticket sales and their main source of revenue is from concessions so maybe the ticket prices don't have a lot of margin and cannot be discounted and made affordable for lower cost streaming.