Unless the player goes through her dialogue tree in exactly the right way, she will never become a companion. The character Veronica is a perfect example. Many of these are hidden in dialogue trees that are hard to maneuver. Nearly ever mission in Fallout New Vegas has multiple options to complete it. While the game is open world, the plot spends too much time directing players where they should go rather than allowing them to figure things out for themselves. Additionally, the giant branching dialogue trees mostly leads to the same conclusions, the factions have very little influence on the character and the companions are loyal to a fault.
The Outer Worlds lack New Vegas' subtlety and consequences and suffers for it by not being quite what fans are looking for. Fallout New Vegas made every play through feel like a completely new story depending on how a player handled a situation, and it did so by making some options less obvious to a player than others. The game had giant, branching dialogue trees, many compelling companions and different factions.
New Vegas had everything fans could want from a modern Fallout game.
Obsidian is responsible for arguably the best Fallout game, Fallout New Vegas.
