It's really interesting to hear the interpretation from your generation. I am the SITC generation. I'm the same age as Carrie, Miranda and Charlotte were in the show. I stumbled across it halfway through the first series in 1999. I was 33 years old, single and living in London. Whilst my life wasn't as glamourous (nor did I get as much sex as those girls did) the show did hit upon many issues that were relevant to me. It's frankness about sex was revolutionary then. It's funny how you talk about the slower pace of dating communications. Actually I don't think it has changed that much. If I had tried to contact a guy (by text or on the phone) and he didn't get back within a day we were pretty obsessive about what might be the reason and whether we'd hear from him again. Maybe we didn't give up so quickly as you suggest - though I'm not sure that's a good thing.
The book - He's Just Not That Into You was revolutionary for me when I read it. Like the girls in the programme I think I was too needy and let men get away with too much crap.