My DBF has a chronic lateness problem - but he is getting a lot better, with help from me.
He was 30 minutes late for our first date (I'd known him for 6+ years at that point and knew he had punctuality issues, otherwise I would have given up!), and he's notorious amongst our friends for being 30+ minutes late for most things.
Since we've moved in together, things have improved, and I realised that for him it's largely a problem of having no idea how long things take. He'd start getting ready to leave 5 minutes before the start time of an event other side of town because 'it only takes 5 minutes to get there'..
Threats, tears and some serious talks later, he no now longer needs persuading that I am in fact correct when I tell him our timescales for getting places on time. Consequently we are now on time for everything (I like to be bang on time+2 minutes depending on what it is), but it's taken a lot of work, and I'm sure he is still late for things where I can't make him be on time.. I'm still training him in mastering the art of 'ringing when going to be late'. Yes, I know it might make you later. Yes, it's still important you do it..
As for why wait? Well, if someone is good company, and they're predictably late, then it's doable, as long as you have very low expectations. One of the problem is late people never experience the sheer irritation of waiting for someone who is late, which I think can be the cause of the 'what's all the fuss about?!' reaction. I've tried being late for things to show BF what it's like, but a) I find this hard, and b) he's normally still later than me, so it doesn't work.
In the original OP, I would gone, and then left after an hour, tops. And then never repeated the experience. Even BF has never been later than an hour!