I agree that they don't realize it. But I actually think the primary reason, for most people, is anxiety. That anxiety can stem from:
- Being afraid of toxicity, not understanding the difference between different types of parties ie. [Practice] vs [Duty Complete], or not understanding all the raid terminology such as DPS in | Relative | BD | TN | Tank LB3, colors, etc.
- Thinking that they are not good at the game. Sometimes these feelings are incorrect (they are good enough), and other times it's an accurate assessment to say they are not very good yet, but they probably just don't understand a lot of basic things yet.

Anyone that thinks gear is a barrier in this game is a minority, and the recent posts on these forums certainly don't reflect the primary reasons for people avoiding it. There are people who lack gil to buy gear, but those people obviously just returned to the game and don't hardly play it and thus don't accumulate gil, not that they need it because gear drops from the normal raids.