Over 13 million bison were slaughtered for their hides and shipped to the East coast and Europe. Why do we not see any sign of the finished hats and garments today?

Because those things would be at least 120 years old. Most garments and fashion accessories don't last that long. They wear out, go out of style, etc. and get thrown away. The only way any item might still exist today would be if it was deliberately preserved.

First the vast majority were killed and left to rot where they fell. That was a war of attrition to starve out the plains tribes and had very little if anything to do with commerce.

It is estmated that the bison herds once numbered some 40 to 60 million animals. Quite apart from the fact that things wear out with age ...

Large numbers of bison were killed as part of a deliberate policy directed against the aboriginal peoples in the west. Many plains indians were dependent on the bison for their basic livelihood, e.g., food, furs, tools, religious purposes, etc. Destroying the bison resulted in the starvation of many and reduced the remainder to such a state (i.e., privation, poverty) that they could be rounded up and relocated to reserves, their land given to immigrants. Some bison were stripped of their hides for commercial use and their carcasses abandoned. Others were simply left to rot. The killing was done as official policy by the US government.

Reply: Apart from the handful in museums, things wear out in time (as stated), or they were no longer wanted and went to the rag trade, or they rot if they were not processed properly, or generations of bugs have enjoyed them for lunch. Where are the millions of socks and shoes manufactured prior to the mid-19th century? On the other hand, if a garment did not exist because the animals were killed and left to rot, how can it exist now? Rotting bison leave only their bones, until these are ground up for fertilizer. Such was my point: a significant number weren't killed to create garments.

back then everything got worn until it fell off of your back

They're organic, they rot. You'd have to look in the Old World dump sites.

we only see what we look for. maybe your looking for the wrong thing or in the wrong place. or maybe there was never any bison and the government created this to cover up a top secret mission. remember the manchurian candidate.