Frankly, I think it's because too many parents try to control every aspect of their teenagers lives at a time when the teenagers are trying to figure out who they are as individuals and trying to take control of some things themselves and feel empowered over their own lives.
That's why I've mostly left it to my kids to make their own choices - both good and bad - and deal with the consequences from them.
They've learned some things the hard way, but that's part of growing up and maturing. And I don't have any communication problem with them at all...well, most of the time. ;) We discuss good and bad choices, I tell them my opinion, then I let them decide what to do. For the most part, both of my teens have made very good choices and we have mutual respect for each other.
There are a couple of things that I do not waver on like their education. So when I do set down the rules, they know I mean business and that it's because it's something that I consider vitally important.