I have no issue with my son not fond of being the center of attention (in fact, it is so me). But I think he is too introverted and needs to be more outgoing, for his own good in the future.
I can understand why you say that, but forcing him into situations he is uncomfortable with is not the answer, believe me. Is he an only child? If he is then you need to provide opportunities for him to meet new people/kids in a safe way.
Trying to change his basic personality won't work, but encouraging good social skills could only be a good thing. Is he fearful, or just not inclined to be more "social"?
You can't change a kid's personality - that's who he is. I think it's best to accept that he is introverted but give him opportunities to socialize. If he doesn't take the opportunities, talk to him about it but don't push him to do things he doesn't want to do because there will be consequences.
If he is naturally introverted, maybe there are things you can focus his attention on that will build on his natural strengths, which would give him a different kind of attention, but still good for him.
I agree with the thread starter. Being introverted and not being able to talk to people with confidence will only hurt anyone when it comes time to getting out in the real world and finding a career. Generally, people with little social skills don't make much money. In business, you have to be able to talk.
Some kids are really good at this, I was the shy one growing up and my sister was exactly like your son. In some ways we turned out completely opposite of how we were when we were young too.
I don't think it's a good thing to push kids to be something they are not. Certainly we all need some level of social skills, but I would never try to force my child into something they were truly uncomfortable with.