He's not wrong exactly, but to a certain extent the market has spoken. A critical mass of people would prefer to watch quiet dramas in their own time and on the setup they control. The takeover by HD and the proliferation of bigger screens and soundbars or easy home theater solutions has created a "middle space" where the average viewer has something that, while not a proper cinema, is miles ahead of the 480i standard definition nonsense we had at home in the 90s and earlier. Then, at the other end, those same trends have allowed some percentage of connoisseurs to invest their resources into home theaters with curtains and posters and tiered seating and the works. Any form of home viewing, of course, avoids the scheduling and interpersonal downsides of going out to see a movie.
So, these types of films are getting squeezed at both ends. Most people will just catch them on their 50" Roku 4K from Walmart and be happy with that. Others who appreciate getting to 95% of the "cinema experience" will watch on their fancy projector and surround sound system. The only people left are the ones who value the communal experience and/or that last bit of quality presentation. If that's not enough to support wide distribution of "adult drama," then I just don't know what to tell the auteurs. For all the same reasons we don't bother with many lowest-common-denominator revenge dramas on the live stage, we're not really going to see a ton of prestige character pieces scheduled into the limited slots at the multiplex.