Here's why (Luke 12:18) "And the rich man said to himself, what should I do my barns are full, I know I will tear them down and build bigger barns, then I shall say to my soul take ease and eat you have much laid up for many years, but God said to him YOU FOOL, this day your soul is required of you then who shall these goods be?" in this verse you can see, why they need more, it does not even enter their mind that their time is short, they have pushed from their minds the warning from God " IT IS APPOINTED UNTO EVERY MAN ONCE TO DIE AND THEN THE JUDGMENT" They are rich but not towards God,. We are all deceived when we, LAY up treasures WITHOUT considering God" that's why Jesus told us, "Don't have all your treasures here on Earth, where rust and moth eats them and thieves steal it, but lay up treasures in heaven were neither moth nor rust does corrode, and thieves do not break in and Steal, for where your treasure is your heart will be also"