How much effort have you put into exploring contemporary songwriters?
I would confess not all that much. But in a way that makes my point. During the 60s and 70s you didn't have to search high and low or put a great deal of effort into finding great songs. In fact, it was hard to miss them. All you had to do was turn on your radio (yes, we listened to the radio back then) and you couldn't avoid hearing great songs.
I'm sure that the young artists suggested by many in this thread are fine songwriters, and I don't think (or at least I hope not) that Mr. Beato is suggesting that all modern songwriting is pathetic. I'm certainly not. But great songs are hard to find these days and I highly doubt that in 20 years, or even 5 or 10, very many people will be listening to the ones written by today's contemporary artists.
By the way, you've brought up singer/songwriters like Ray LaMontagne, Norah Jones and Mia Doi Todd (haven't heard of her), but as you point out, they're all in their 40's and 50's. That's not ancient by any means, but they don't really fall into the category of young contemporary artists.