This is completely false. Moving the 9-ball to the spot favours those with stronger breaks. With the 1-ball on the spot the wing ball is practically wired, and almost anyone can step up and make a ball on the break. The 9-ball on the spot makes the break a more skillful shot, favouring the better players.
In my experience, whenever your argument is along the lines of, "because that's how it's always been"... you've already lost.
Not without a box and dry break rules, with 9 on the spot the 1 becomes fixed to the side for any lesser player who can make a ball now by breaking with soft speed, which is much less difficult than breaking with higher speed and requires less practice.
With too small box doesn't make a difference anyway, most breaks don't make a ball and he who has practiced the break is the "fool" while the one who hasn't practiced the break is the "clever" one...
Let's be honest: all these things started a while ago in Europe when a generation of the same players used to win most tournaments, and the next generation after them that had less will to practice hard enough in order to run out more stopped going to tournaments.
Directors changed the rules in order to increase participations again and for a while that was the case, but in the long run it has hurt the game.
I'll state it again, there is no other sport worldwide where a player which deficits in any part of the game is supposed to win (by altering setup) against a player which is better in all parts of the game, and the break is a part of the game no matter if we like it or not.
So if a player is afraid of his pro opponent to run out the set on him, he only has to practice his soul out to do it before him.
That is what competitive pool excellence is about, not giving the 5 miles/hour breaker equal chances of winning because he doesn't have the necessary talent for a big break and he's not willing to work hard to improve it, along with his consistency in position and running out.
That's the truth.