The industrialized North needed great amounts of leather for belts to drive the new industry's war machinery.  Buffalo were killed solely for the hide to provide leather for those belts to win the war for the North, and deprived the plains Indian population surge of it's greatest resource.

Wyatt Earp didn't come into the West until most of the buffalo were already gone.

Are you confusing 'Buffalo Bill' / William Frederick Cody'   with Wyatt Earp ?

Buffalo Bill killed a great many buffalo; some  in a contract to feed Kansas rail workers some for title and sport.

Wyatt: if any action, diverted his freight wagon around the dead carcass of buffalo. 

Nothing.  The meat was indeed left to rot.  They just wanted the hides.

Native Americans had use for all parts of the buffalo. The buffalo provided staples considered necessary for survival. When the white man began hunting buffalo, the way he wasted most of it was particularly offensive to the indians. Once the white man got what he wanted/could merchandise, the rest was considered excess and not cost effective to transport and process.

Actually, they just took the few parts they wanted and let the carcass rot.

Wyatt Earp never killed a buffalo let alone skinned one.

There is no confirmed reports of Earp actually was involved in the buffalo hunts.  The big hunters were Buffalo Bill Cody and US Army officer Phil Sheridan.

The reasons for the waste were:

1.  The money was in the hides which could be more easily transported.

2.  The whole point of killing the buffalo was to cripple the native people's way of life.  If they had nothing to eat they would have to go to the reservations.

they let it rot or left it for the scavengers, whichever way you want to describe it.  They were being paid for the skins.