Friendships coming to an end

Just a quick question...

Would you remain friends with someone you felt has changed into who they never wanted to be--the complete opposite of the person you became friends with in the first place?

Because this is happening to me. At first, I tried to see that these changes were for the better and that she was becoming a happier person. Now, I realize that she's being happy for the wrong reasons such as partying, drinking, having boys lust over her, and being way too involved with materialistic things. She's not around when you need her and then she makes excuses for it instead of saying sorry. If she does apologize, I never feel like she actually whole-heartedly means it. She thinks that I'm stubborn and mean. And I am. I have always been that way, so why does it come off as a suprise now? I'm not the only one who feels this way, our whole group of friends does. So how can a group of people be the problem as opposed to one? Does democracy count in these types of things?

We both really just need to let this friendship go...as sad as it is, but it's not going to work out. Our personalities clash and we wont work on anything to make it better.

I really need advice or someone's input. I don't care if I know you--I need people's opinions in this.