1. Do you mean a meaningful life from the gamers perspective or from the perspective of outsiders?
2. If the issue is lack of self-esteem etc. Wouldn't it be better to focus on mental health instead of employment? Once again, I was interested in talking about gamers who are happy with their situation.
If you can derive meaning from your career, that's great. Otherwise, family or contributing to society or whatever you think makes a difference in the world and is worth working toward.
Like everything, gaming is great in moderation, but the gamer who does nothing with their life but game is probably going to have some regrets on their deathbed.
You have also used another word - meaning. Is that a synonym for principle?
I am sure the gamer interacts with his parents. I couldn't find anything in the medical literature about excessive gaming either. It is quite possible that he may have regrets on his deathbed like most people. However optimizing your life for the thoughts you will have in your deathbed might not be a great tradeoff if it means doing work that makes you miserable for most of your life.