It is very natural that people don't realize this, since it is NOT something anybody every taught or even told you. People just take their "personality" as granted. Which is cool.
You, in DP, have another perspective, you kind of "realize" that our personalities are kind of mind-created "illusions", but you also come to the wrong assumption that it is a kind of destiny. Some people say that "depersonalization is an irreversible insight into emptiness", also call it "enlightenment's evil twin".
Truth is, you can EASILY go back to having a self, and to have a fulfilling life, just like everybody else.
To be honest, you'll probably have the potential to be happier than the average Joe (sorry, Joes), because after DP, you know that you are free to be anyone you wish.
But this freedom can become a trap. When you have the opportunity to become anyone you wish, you may tend to jump between different "selves", and someone who has 2,3,10 different "selves", basically has no self. Because a self has continuity.
So, what you should do? Easy. After you came out of dissociation (because it is a neccessary first step), you should just decide who you want to be, and build your life around that "person". Only include things that fit that "image" (which is a self basically), so it feels coherent.
This will give you a place in the world, an "ego", a scenario so you can relate to people, things and places.
It is really, really, really a simple thing to do.
But beware: In depersonalization, especially if it lasts for years, we tend to "play around" with thoughts like they are nothing. On this road, you will realize that your thoughts are pretty powerful things. Thoughts can build but can destroy just as powerfully. Watch your thoughts.