I think that some of you need to read
The Science of Hitting in which Williams says:
"The flight of the ball is
down (see diagram -- not included here), about 5 degrees. A slight upswing--again, led by the hips coming around and up--puts the bat flush in line with the path of the ball for a longer period--that 12- to 18- impact zone."
"...But if you swing slightly
up you have to have the hips leading and then out of the way, generating speed and power, and you will find your top hand (right hand for right-handed batter, left hand for left-handed batter) is in the strongest possible position: wrist unbroken and directly behind the ball at impact. The result: a ball is hit with greater power and authority.
...Certainly there are times when you want to think more about getting on top of the ball--times when you are having trouble, getting fooled, popping up...When I say 'get on top of the ball,' I don't mean to swing down or chop, but to get your sights higher and level out your swing more."
...
"Ground out a lot? Your probably swinging too early. Popping up? Probably swinging late. It's a slight
upswing, remember, and when you're late, your're under the ball, when you're early you're on top."
Williams wasn't advocating launch angle as we know it today; rather, he was preaching a swing that kept the body in the best position to hit and one that kept the swing of the bat in the plane of the pitch as long as possible to provide greater frequency in getting hits and to hit with power. When people today claim that Williams was the basis for launch angle,
ipse dixit comes to mind.
But as a slight aside to this, there is an interesting article from the Sports Illustrated Vault, April 14, 1986, with Williams spending quite a bit of time discussing hitting with Wade Boggs and Don Mattingly (with an occasional question by Peter Gammons).
https://www.si.com/vault/1986/04/14/633776/a-real-rap-session