system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokemon] Are gym leaders in the order they are because they WANT to be, or is it an indicator of their skill?

Like, some gym leaders are older than others, you'd expect the older spectrum of trainers to be stronger, but sometimes we see adult gym leaders earlier on and then 6,7,8 gym leaders are sometimes even kids! 

Are they in order of skill or do the gym leaders just prefer to be where they are? For example, can the first gym leader hold their own against one of the Elite 4? 

I ask this because, for example, Lt. Surge should've been a member of Elite 4 or Champion just because of the fact the guy was in a war and should be a master tactician, yet he is merely the electric type gym ~level 20 pokemons.
gpt
The explanation in the Pokemon Adventures manga and Pokemon Origins series, which are the closest adaptions of the games, is that the gym leader chooses their Pokemon they fight with based on the number of badges the other trainer has. This explains why in Gold & Silver for example, Brock has higher level Pokemon than Lt. Surge.