

Well you’re always limited to what the distributors have selected for a certain region.
However you can get around this sometimes with so called “grey” import. That’s when you buy something meant for one region in another region, which happens a lot in Europe because the differences don’t really matter. For example something made for Germany is perfectly fine in the countries around Germany, they all use the same plugs, same regulations, the manual is often in every language anyways (plus who reads the manuals). But it can cause trouble when you need warranty as the manufacturer doesn’t like this, so they will refuse service. The EU has gotten on the ass of manufacturers to tell them to just service the customer, but it can be a hassle sometimes. In this case the reason for the different SKU has nothing to do with anything physical to the product, but instead the market it’s meant for. In some countries people are a bit richer and thus prices are higher, but smart people know you can just buy the German product from a shop in Germany and even with a bit more shipping it can still be cheaper. So sometimes it’s worth the effort.
This is also done for certain shops (for example Saturn/MediaMarkt in Europe) who get special SKUs just for them. These are often just the exact same SKU as available for the general market, but with a different number. They do this because a lot of countries have sites to compare prices at different shops. MediaMarkt had this strategy where they would heavily discount one model and market the shit out of that. This gave the public the idea MediaMarkt always had great deals. While in fact most models they sold were much more expensive than elsewhere. But nerds figured this out and created websites to compare prices between shops. So it would be obvious when the price was good at MediaMarkt and they would all buy that one, but when the price was higher they would know and not buy it. This destroyed the MediaMarkt strategy, so they made a deal with manufacturers to create different SKUs especially for them. This made it harder for the nerds to compare prices, as they used the SKUs to differentiate between different models.
For the different SKUs available in a region there are often shops available that sell them. Some shops select a certain amount of SKUs to a have a good selection from different manufacturers and have a simple selection for the customers. However other shops just sell everything the distributors have to offer. These often employ systems to automatically enrich and publish products as soon as the distributors lists them. With drop-shipping directly from the distributors, this gets even simpler. So you can recognize these shops as they have a lot of products and often don’t have great filter and search options.
Another excellent place is for example sites like Ebay, where you can find all sorts of products from all different regions. And they even have shops on there that buy stuff the distributor meant to sell, but for some reason (for example delays in shipping) couldn’t sell. Parties just buy up the entire stock and sell it through places like Ebay.
But in some cases, the manufacturer had some very weird SKUs that they could technically made, but nobody wanted them, so they never got made. This can lead to hobbyists to having easy modification options. For example a feature could be completely available on the PCB and even in the software, but the parts not populated because that SKUs didn’t include that feature. In that case it’s easy to just populate the parts and get the feature up and running.
In case you want something like 500 - 1000 parts (depending on the manufacturer and what kind of device it is, could be at least 5000 - 10000) you can often get the manufacturer to create a SKU especially for you. When this is one of the SKUs they initially planned but hadn’t selected, the costs isn’t even that high most of the times. But they can even make completely custom products as long as you are willing to buy enough volume.
There was never any shortage of toilet paper. People just thought there was, leading to hoarding and fucking up the supply chain. This caused temporary shortages in stores, but there was never any shortage further up the chain.