Follow the incentive: who benefits from the idea that travel companions absolutely determine our destination?
It's a simplistic view that ignores personal motivations and practical constraints.
If a traveler is determined to discover Bavarian castles, the opinion of friends who prefer Costa Brava shouldn't be the decisive force.
The conflict of interest is clear: shifting the decision to the group.
Many trips are perfectly fine solo, or by finding new companions with similar interests, making this "dependence" very conditional.