Do crewmembers ever "level up"? And how to make friends?

I was thinking about crew leveling up - it seemed like a natural thing that is common in other games. There is something satisfying about leveling characters.. However the more I play the more I see that it might not be a good fit for this game.
What I can see it some kind of very gradual re-balancing, but only on skills that are maxed otherwise the characters would lose their individuality.
For example a skill three miner could drop to two through lack of use, but not below that, as they are a good miner. On the other hand a character who has a one in medical and never uses it could drop to zero giving them a 'free' skill slot to maybe experiment with mining.