Leather has been a valuable commodity for centuries, so much so that it helped develop the American global economy. I'm sure I don't need to go into how useful it is as a material, but before the modern age it has been used for things like book bindings, vellum for writing, upholstery, footwear, and even clothing. One such garment popular in the 18th c was leather breeches which became almost the blue jeans of the colonial period for it's comfort and hard wearing characteristics. After a European cattle blight in the early part of the century, leather became scarce and this expensive yet the fashion continued become more favored in the upper class.

To satisfy the demand for leather, Europe needed to look no further than the North American colonies cocked full of deer. Native American hunters harvested and traded deerskins to their allied English merchants which shipped hundreds of thousands of tons of hides to England annually from places like Charleston and Savannah. This trade created a market for European manufactured goods provided to Natives, provided raw materials to a growing European manufacturing core, and helped to cement alliance between the English and neighboring tribes.

The fashion of the buckskin breeches flourished as prices settled and almost as long as the practice of wearing breeches, until the popularity of the trousers prevailed in the early 19th c. This change in taste coincided with the scarcity of deer, nearly hunted to extinction around the turn of the century. Prices climbed again.

We see the same phenomenon in beaver hides which were used to make hats between the 17-19th centuries. Beaver pelts sourced in North America helped to drive the productivity of the beaver fur hats which results in popularity. With demand comes the trapping out of populations and a decline in demand as prices skyrocket. As a new fad comes into play, prices of the original thing again fall without the demand until a new source is found in the rocky mountains beginning around the second quarter of the 19th c which again coincides with the rising fashion of the early victorian beaver top hat, once again brushed aside by silk plush from France as the western beaver is nearly annihilated.

With the advent of the automobile, a new need for leather upholstery is required to furnish vehicle interiors in the 20th c, easily met by the byproduct of the cattle industry. What else besides the cow becoming the chief source of leather again is happening? Airplanes and motorcycles by the 1930s are now a thing and virtually operated exclusively by leather jacket clad cool guys that cement the leather jacket as a staple of western fashion even today. Popularized by new media like movies, the leather jacket becomes associated with heroic pilots from Amelia Earhart to Lt. Pete "Maverick" Mitchell and rebel bikers from Harley Davidson to Marlon Brando. By mid century it infected the music culture into the early 1990s.

That same popularity bleeds over internationally as Asian culture adopts Western trends, and with faster growing populations to boot. With the ever increase in demand it only takes a drought, changes in beef prices, a cattle sell off, rise in feed prices, or a reduction in grazing land to cause leather costs to rise greatly. We're currently experiencing all of the above. To make a short story long, fashions change, so do leather prices, and it's been going on since forever.