This tendency to stay in the default choice is called default bias (or status quo bias) and encompasses people's tendency to choose inaction over action as well as their preference to stick with previously made decisions.

This is a prime reason why people don’t want to change parties when voting: A lot of republicans did not like Trump, but they voted for him because “that’s what they have been doing” for decades and that’s how they were brought up. That was the most comfortable thing for them to do.