Why is old music so much better than new music

I just don't get it

Sale 1

http://www.tf2outpost.com/trade/26574098 Sold for Pro KS S. Original

B/O for Whoopee was 15

B/O for Original was 15

X = 14.9*0.9

X = 13

Original https://backpack.tf/item/1541492837

Whoopee https://backpack.tf/item/1353595891

Sale 2

[No OP Trade] Sold for Bubbling Marauder

X = 13*0.9

X = 12

Marauder https://backpack.tf/item/1352756293

Whoopee https://backpack.tf/item/1337699864

Mini for Marauder

[No OP Trade] Sold for Blizz Snaggle + White Bruiser's Bandana

X = 12.5*0.9 + 2*0.9

X = 13

Snaggle https://backpack.tf/item/1339472483

Bandana https://backpack.tf/item/3782002545

Marauder https://backpack.tf/item/1343351774