Why don't guys commit?

In regards to my last question about my best friend..

We finally had a talk, he made it very clear he had feelings for me. For the first time in four years he verbally admitted that he liked me. It felt good, until he told me that he didn’t want a girlfriend.

You know, I can normally understand these things. In no ways am I clingy, I actually prefer not to date people or have that kind of title. When it comes to everyone but him, I run the opposite direction when the big status question comes up.

So why am I so devastated that he won’t give me a chance? We obviously care for each other and everyone always tells us they can see our chemistry, and we act like a couple. But if he’s not willing to commit now, then when? I don’t want to waste my time, but I don’t mind waiting if I know it will eventually come.