Raw hides take about 1 to 2 month to be transform into leather using the vegetable tanning method (the best). With that said I'm sure I would never have any difficulty to obtain simple blank hides with natural color and no finish. The problem arise when you start looking for finished hides.

Each tannery have their own technique to obtain their finish. Badalassi Carlo has this beautiful pueblo I use a lot. A very distinct look. But they have only one tannery to supply the entire world. There's many suppliers around the world that has stocks so if you really want a hide you can find one but your favorite supplier who can satisfy your thickness desire might often run out and the supply chain is not as fast as Amazon. I'm currently stuck waiting a month to get my hands on tabacco pueblo. But the REAL scarcity is found in shell cordovan.

Shell cordovan is a rare, high-end leather made from a small, dense layer of fibrous tissue found in the rump of a horse. My favorite one is the Japanese shinki-hikaku. The process take from 6 to 10 months. There is only a couple handful of hides available in any given color. They are very difficult to obtain reliably and are all sold individually. You buy a specific hide. There is an orange one at my main supplier. Only 1 left out of 3. I haven't found anywhere else I can get it. Maybe it's possible to get it elsewhere, but I haven't found it.

Note that this is my experience as a small retail. Big businesses might have an easier time than me getting their hands on some of these.