Because the characters and the story have to be balanced. By giving your character power armor and super weapons, the combat balance has shifted. You also have virtually no weaknessed.
But that would work for something like the Kilrick RPG. Here, armor and heavy weapons might be a plus.
But in Lone Wanderers, the characters are generally using light armor- leather or some kind of composite. The weapons are general small arms.
We have had power armor, mini-guns, power weapons, etc. But these have been few and rare instances.
They will also show up again. But the idea is to make it realistic and tricky, give your character more weaknesses and vulnerabilities than strengths. The theme is more like the beginning of Fallout when your character is just getting started and finding an SMG is a bonus.
Again, you need to familiarize yourself with the RP as it is. Lone Wanderers has been going on for over a year now.
There are lots of posts and there has been a lot of commitment to the game. IT is more a cooperative novel than an RPG, and in many ways its the creation built from learning of many past mistakes on RP.
While the players are accommodating to new players, there is a bit of expectation. That you commit, that you write well, that you write good posts and that you understand the rules of the game. We are easy going on a lot of that most of the time. We do disagree but generally we cooperate and work together.
That's why a lof of us are suggesting that you read through the posts (and even past the chapter summaries) to understand what's going on here.
THat's also why we are initiating new Role Plays, so that people who are unwilling or unable to commit to something like Lone Wanderers can enjoy Role Play in a more traditional form.