In the real world, half the volume would mean half the employees.
And that’s about the drop since 2000.
I hate to keep repeating myself, but you’re clueless. When I first started 30 years ago a big day might be 10 packages. Now, I average close to 100. What do you think is more labor intensive? Letters or mail? It’s not rocket science. New employee turnover is so high I don’t bother to learn names until they last 6 months. Which is a rarity