Curious thing about anomalies - you never know when they're going to come along, or why they do, but eventually they do. Like Barack Obama, for instance. How did he get here, when the world was so mired in wrongness? Yet, here he is.
I look at Dire Straits the same way. The late 70s in music was not pretty. So much dreck. Out of the blue, there's Sultans of Swing - a song so nuanced and startling that people sucked it up as if starving. Maybe it's a law of the universe that, after a steady diet of junk food, an organism will want to snap out of its unhealthy ways if given the opportunity to reverse the damage. As Peter Buckley said in The Rough Guide to Rock, "Despite the prevailing trends of punk and disco, the band's well-crafted songwriting and skilled playing unexpectedly appealed to over 7 million record buyers."
According to an interview with Guitar World, which crowned the song #22 in its compilation of the 100 greatest guitar solos of all time, Mark Knopfler wrote Sultans on a National Steel guitar in an open tuning, an arrangement he found "dull," and which he never played that way. A simple instrument change - to a '61 Stratocaster - made it into the thing of beauty it is today. (Muff Winwood, Steve's older brother, produced it.)
None other than Chet Atkins described what makes Knopfler's playing so distinctive. In addition to dispensing with the pick, "... he's a lefty playing right handed, so he's got a lot of power in his left hand. He can make a vibrato on multiple strings better than anyone I've heard," he says in his book Chet Atkins: Me and My Guitars. The two got such a kick out of each other they recorded an album (Neck and Neck) in 1989; here's a nifty clip of them playing together.