Over thirty years ago, Albert O. Hirschman wrote a book called Exit, Voice and Loyalty.  I hadn’t heard of it until today, though I may now try to get hold of it, having across this comment which draws on its concepts:

Exit and voice can be substitutes and reducing exit may increase voice.  But more often than not, voice and exits are complements.
When you complain of delay where is your voice more likely to be heard;
at a restaurant or at the department of motor vehicles?

It’s the threat of exit that makes people listen.

Issues of exit and voice have clear implications for our strategic thinking, particularly in the several ways we could attempt to move towards more constrained routes for customers, staff and others who do business with us.

If we reduce or remove exit, how do we protect voice?