I think you are confusing shyness and introversion. Introversion is when you don't feel the urge to talk, to act unless it's important or valuable. Shyness is when you want to talk, you want to act, you want to introduce yourself to that person, but you are unable to do it because anxiety kicks in. Actually the more thought you have put into what you want to say, the more it's important to you and the more emotionally involved you are, the more you are afraid to be misunderstood or rejected and the more you are likely to shut up. So a lot of shy people, when they get to talk, will often stay at the level of useless small talk because it feels safer.

Western culture certainly values too much extroversion, it should certainly be more kind to shy people, but in my opinion shyness is not something to celebrate, it's really handicapping in a lot of matters important in life and it doesn't bring anything to anyone.

Not necessarily. If a shy person does speak up, you know that they've put a lot of effort into doing so. Therefore what they have to say is important, at least to them.

Although shyness and introversion are not the same thing, I think they are closely linked. I am introverted and shy. Because I am introverted, I do not often seek out the company of others, and conversation does not come naturally to me. I am painfully aware that I am not good at conversation, and that becomes foremost in my mind when I anticipate engaging in one. It's like joining a hockey game when you are not a good skater. You just know that all the other players are going to notice how good you are not, and that you being there is making it less fun for everybody else. This anxiety causes you to avoid playing hockey, which just makes the situation worse because you never practice.

What you're saying sounds more like social anxiety than shyness. There's a difference between the two and shyness is more about being bit overwhelmed of new social situations than to be afraid of them.

That's alright for the other people but it's no use for the shy person themselves. They still won't get ahead like the extrovert who says a lot of crap and people like them for it.