Moving preload back an hour and a half moves everything back an hour and a half. No more late pickups for high volume shippers. All the sorts would have to move back an hour and a half. Even if you ignored all of that, you still aren't moving volume any faster over the ground. So packages that could be delivered in 2 days are now taking 3 days. More 1DA, 2DA, and 3DA volume would have to go by air to make the commits. It makes it all more expensive.
Here you go again confusing people with hard facts.