I don't see it as a binary choice.

I see it as a good goal, but HOW you do it is very, very dependent on the circumstances.

Sometimes, you can best collaborate at the table by opposing the other players, bringing better stories to light. Other times, leading in your own tale. In still others, acting as supporting cast in someone else's story.

As such, I see it as a personal preference as to how much of a background you bring to the table. No background, no matter how individually focused, precludes future collaboration & growth. In fact, it's not a bad thing to show - the egotist becoming more aware and part of consensual reality. In other cases, one or many (or even all!) egotists in a party can tell other interesting stories!

In short, it comes down to the chemistry, the goals, the intents inherent within your current gaming group, in my mind.