Will we ever know how much they think it will? Their own stats tell them that 5% is not going to bring them back to 1990 distances (if that is even what/when they wanted). I have a stronger suspicion that the 5% was simply the figure they felt would be most palatable at this time. They haven’t closed the door on additional measures … or even additional distance restrictions.
As for money attracting better athletes … maybe? Though money is also a two edged sword as it might cramp motivation. Note: There was just an article out, last month, listing sixteen players who have reached the $10 million career earnings level without a single victory. Not bad.
And, as to depth of fields … well, that’s an unsolvable chicken-or-the-egg type question. Perhaps the fields only look deeper because the equipment has leveled the playing field? The only way to truly find out … is to put the cat back in the bag, and right now, as their plans stand, it appears to be only about half way in.