In my experience you can learn more about company culture by asking about places where the effects of a culture are visible, rather than by asking directly about the culture itself.
So, ask about the areas where the things you've identified as being demotivating would present themselves (without leading the interviewsinterviewers by giving your preferences before they've had a chance to answer). For example:
What started as "we are a family" slowly turned into "Every man for himself".
You may be able to learn about this sort of attitude if you ask about processes the team follows, for processes that you would expect to include strong collaboration.
For a software job this may include things like code reviews, retrospectives, or what happens if "the build" is broken.