I think he is saying what a lot of fans fans feel. There could always be more of those risk taking films made but I don't it its a bleak market. More could be made for sure.
However he's also speaking as a director who probably feels personally slighted. Some films he has succeeded in getting made probably took long periods of time to get made because of money, and some films he wants to do won't ever get made because of money.
Box office shouldn't be the sole purpose of course, but look at the budgets of his films, and many other 'auteurs', you've had to put asses in seats for those budgets. It's no surprise execs aren't taking chances, as they're the ones who have to deal with a Hugo or Silence not making any money, and not him or these other directors.