iPod Classic's Storage was More than the One's of Today?

Why is it that the old iPod classic's 120GB and 160GB were able to store 20,000-40,000 songs, when the iPod Touch's of today, 32GB, 64GB or higher, can only store 4,000-8,000 songs?

Why can't mp3 players of today store 20,000 or more? What do you think the reason is.

via iLounge Forums http://ift.tt/2dyclJ3