I'm joining the chorus here and agreeing that your former friend was in the wrong here.
I am married to someone who is late to almost everything, even including, sometimes, her job. (I know that because she won't ever check messages on our landline voice mail, and I'll hear the calls from her workplace asking about why she's not there yet.) It used to drive me absolutely up a tree. Early in our marriage, before we had children, we missed an international flight because she would not get herself ready to go in time to get to the airport. I decided at that point that, to stay sane, I would have to make my own arrangements to get myself places on time in my own car. I learned to get ready on time myself, and then tell her what time I was leaving, and then if she would not get herself ready, I would just go ahead and leave in my car at the appropriate time.
It made me very sad to do that with our children, too, but when they started being late for school several times each week when they were very young because she would not get herself ready to walk them to school on time, I'd see that the kids were ready and then we'd walk out the door without her. (That's a horrible thing to do, walk out the door with your kids and just leave their mother behind, still putting on her makeup, but that's what it took to get them to school on time.)
I don't understand her way of thinking - or not thinking. For example, my wife would watch certain hobby-related TV shows for several hours every Saturday morning, even on Saturdays when she needed to be ready to be somewhere at noon or 1:00 PM. Then she would be late for those Saturday appointments, but it seemingly never occurred to her that she was late because she didn't start getting ready until after her shows were over. She would be flustered and make vague excuses to other people for why she was late, but she would never acknowledge that she was late because she didn't start getting ready early enough. (I only tried pointing this out to her once or twice. She became furious at me for suggesting that it was her own fault she was late because she didn't start getting ready early enough. I stopped suggesting that.)
Anyway, to get back to you, OP, if your former friend is like my wife, she is unwilling to change, and whether or not she says that she "cares" that it is frustrating to others to be kept waiting, she is going to continue to do that because that is just the way she is and she is not willing to change herself.
It sounds like your friend is a former friend and that your friendship is over. I think that is fine and probably less stressful for you.
If you change your mind and decide you want to be friends again, I encourage you to not count on her to be anywhere at a particular time. As someone else has said, don't buy tickets for her in the future because you already know she cannot be trusted to keep her word regarding time. Tell her what time you are going to leave - or how long you are going to wait for her - and then leave when you said you would leave. She won't like it, but why should you continue to cater to her rude tardiness?