quicken has it right, 2 hander is easier to learn, and so that is what is usually taught to juniors now. What is taught to kids is what they will play with the rest of their life 98% of the time.
Heavier, less powerful wood racket would make the 1 hander harder to learn, but the 1 hander was what was taught back then (Chris Evert hit with two because she couldn't swing the racket with one when she was little).
Rackets, grips, strings, court bounce, etc. don't have much effect because they don't come into play until after you learn how to hit the ball.