You completely misunderstand and you really sound like you never experienced a proper D&D campaign. It never a competition about who's the coolest or trying to be cooler and it shouldn't be because that kind of competition destroys the game. A D&D party is and should always be about being in a group where you and your friends are all awesome together. And if we're being real in a tabletop D&D game a sole character would have a very hard time surviving alone no matter how powerful because every class has key weaknesses that have hard counters...that's why everyone in the party plays a different and vital role. Wizards are powerful but soft, they can't take too many hits, barbarians are often tanks, clerics are often healers, etc. Everyone has a role to play and everyone works together. Nobody in a D&D party is a commoner, those roles are left to NPCs.
I feel like you are conflating game mechanics with roleplaying. You could still be a kickass wizard at level 20 even if you started out your adventures at level 1, fresh from the academy or if you start as a level 1 wizard that was the coolest badass ever and a lover of Mystra herself. In the end, you both are just level 20 wizards with the same power.
