On the subject of no-hitters, the saber types say once a batter hits a ball, there is no predicting where it will go. That means unless a pitcher strikes out 27 guys, he's got to be damn lucky to pitch a no-hitter since every hitter has hit the ball at a fielder--unless he has struck out. Think about it. It's like rolling dice.
You got to be lucky to pitch a no hitter.
Remember that perfect game Larsen pitched in the World Series? And, was it Halladay, later on? That's the ultimate luck. No walks, in addition to no balls hit at fielders, is some accomplishment--considering the subjective aspect of calling strikes.
The laws of probability say these things will happen--but not very often.