Why do I have to update drivers?

Maybe some of you can help me with something that has bothered me for a long time.

When I buy a product, like a video card, and there's a problem with the card working properly, the first thing you are instructed to do is to update the drivers for that card. So you update the drivers, and suddenly the card works fine.

This doesn't make sense to me.

Before there was a new driver issued by the manufacturer, presumably the card would function properly under the old driver, right? (If it didn't, you would expect mass outcry from people who can't install their new cards)

How does the card know it needs a new driver to function properly? It's been sitting in a box for months without internet access.

Why does a product cease to work properly upon the release of a new driver?

- puzzled