It really is the studios fault for not wanting to take the risk and release more of them. The audience is blameless.
I have some time for a slightly less flip answer--
Here's the top grossing films for the past handful of years:
2017: Beauty and the Beast, Ragnarok, Spider-man Homecoming, GOTG 2, Despicable Me 3
2016: Civil War, Rogue One, Finding Dory, Zootopia, Deadpool, BvS. Secret Life of Pets
2015: TFA, Jurassic World, Age of Ultron, Inside Out, F&F7, Hunger Games 3.5, The Martian
2014: GOTG, Hunger Games 3, Winter Soldier, Lego Movie, Transformers 4, X-Men DOFP
2013: Iron Man 3, Hunger Games 2, Despicable Me 2, Frozen, Man of Steel, Monsters University, Gravity, F&F6
2012: Avengers, DKR, Hunger Games, Skyfall, Twilight 3.5, The Hobbit, Amazing Spider-Man, The Brave
2011: Harry Potter part 45345, Transformers 3, Twilight 3, Pirates 3, F&F5, Thor, Captain America, Rise of the Planet of the Apes, Super 8
2010: Toy Story 3, Avatar, Alice in Wonderland, Iron Man 2, Twilight 2, Inception, another Harry Potter movie, Despicable Me, Shrek 4
So what's the pattern here? 95% of these are franchise movies. Or more specifically, everything is based on pre-existing IP, be it a book, comic, old movie or TV show.
The outliers easy to spot. They are either animated family films by Disney or Dreamworks (which are such strong brands they have the same recognition as pre-existing IP to the public), or come from a very short list of auteurs who have a track record that they can do what they want. Basically, there's five guys in Hollywood that can do this-- Abrams, Nolan, Speilberg, Cameron, and maybe Ridley Scott on a good day. There's a few alternates like Scorsese and Fincher who sneak one in there, or guys like Tarrantino or Woody Allen who are in their own worlds making their very specific thing.
Point is, that's a short list of people studios will accept big budget original material from. Again, like Disney or Dreamworlks, these directors have a very strong brand that is basically the same effect as pre-existing IP.
Studios chase the money. They look to things that are proven in other mediums to make money, and they adapt it. They cash in in stuff that's already made money. Or in the case of animation, or this short list, they cash in on the reputation. Sometimes they can cash in on an actor. Johnny, Depp, Channing Tatum-- there's always an actor who has time in the spotlight and can get anything greenlit.
Again, the point-- studios follow the evidence of what makes them money. People flock to these films, so they make more and more of them.
Obviously in the years I listed above there's some original films, but they are never have the money behind them these top tier releases do-- which means less screenings, which means less money made. It's all a formula to the studios-- and what the audience is interested in is a huge factor. There is endless market research done on viewing habits and buying trends to help studios decide on what to make.
So, I'm sorry-- but the audience can absolutely influence what is made. Here's a great example: The Dark Universe.
Universal planned to bring back the classic Universal Monsters in a shared universe-- like a horror Avengers. They built an entire writer's room like a TV show to develop the universe ad hoc, and planned an entire slate of films with characters that would crossover.
They made the first one, The Mummy, and it TANKED hard. It was such a bomb that Universal pulled the plug on the entire project, removed the other films from their schedule, and released the writers. All because the public said "no thank you."
If, as you say, the audience is blameless and has no effect, Universal would be pumping out those movies.
If you listen to the TLJ haters, they take credit for Solo bombing thanks to their shunning. I don't know if I buy it-- but I know for sure that if Star Wars movies continue to bomb the grand plan will be changed.
It's all about the money, bottom line. If vast swaths of the populace stop going to superhero films, or go to see smaller films instead, or simple stay home to enjoy the new golden age of television, the studios will change tact.