Yup my bad Cameron is the man I was writing about.
No clue why I said Spielberg.

Uhm yes.

Spielberg and several other directors have explained this in full in various interviews, which you can find online.

Production cost of movie
Marketing domestic and international
Cut off each ticket that goes to the theatre that shows the movie
Various other costs
Add all of the above up, and you need to make 4 to 5 times the production cost to break even.

Super bowl trailer spots in commercial break went as much as 30 million dollars.

Movies need to make around 4x to 5x their production costs to break even, let alone show a profit.
Hell Spielberg said himself that Avatar 2 actually needed to make 2 billion in order for it to make a profit which is 4.9 times the budget, the same applies to Marvel movies they need to recoup, and they aren't doing that.
The global box office for Marvel movies not counting Spider-Man is down by half for the current phase.

So it looks to me that people are only interested in a lot of the current movie line up, save for maybe 1 or 2 titles like Spidey and Guardians. The fatigue seems to be setting in.

Also didn't help that Phase 4 didn't make any money for them and phase 5 is looking to be worse.
The only movie that made a real profit is Spider-Man and they only get 25% of the profit as the rest goes to Sony, and this will repeat for the next Spidey movie.