Dryden forgot to mention that there was a disincentive for goalies to drop on their knees back in the 60s and 70s. The butterfly style was known (Tony Esposito invented it), but not employed often because the fabric of the pads they used was full of camel hair or who knows what else and it soaked up the water on the ice. By the third period the waterlogged pads would get super heavy, inhibiting mobility.
With the introduction of space-age water resistant fabrics in the 80s, this no longer became a problem and goalies like Patrick Roy could use the butterfly style exclusively. Helmet/facial protection also advanced to the point where goalies no longer feared getting hit in the face, so they crouched more, with their faces closer to the ice and where the puck was coming from.
And that's the big difference right there: The stance. Goalies in the 60s and 70s stood almost completely upright all the time, keeping their heads above the crossbar. They only protected the net with the bottom half of their body. Today's goalies are perpetually crouching, with their heads below the crossbar. A crouching goalie is using all of his body to cover more of the net. No part of him is wasted.
These things have been known for decades and Dryden is not pointing out anything new. For instance: The goalie wearing an oversized chest protector so when he plops down in front he pushes it up past his ears and his head tucks in like a turtle, it takes away the shooting space above his shoulders.... JS Giguere invented that style in the 03 playoffs. They called him the Giggy Puff Marshmallow Man because his pads were so big, and the plop on your knees, pushing your chest protector up is nicknamed the "Easter Island Head Statue" because that's what you look like: A big square block that just absorbs the puck.
Same with the reverse-H technique of protecting goalposts. It's essentially constructing a wall as if your limbs are Tetris pieces and they fit snug against the post like so. If done correctly and in a timely manner there is zero chance anyone can score from the corner or behind the net.
So these issues aren't new. I don't like his suggestions of increasing the width of the nets though. Lacrosse did that and it led to football scores (which I guess is good for excitement but I never liked that much scoring).
But above all what's happened is that goalies have simply gotten better while the net has remained the same. They are better equipped, better trained, better prepared, in better shape, and they're bigger, faster, and more educated in systems and techniques. They have essentially optimized the objective of total net coverage in any given situation as much as they can, and there's nothing the league can do about it.
Except make the nets bigger.
