Apparently it isn't worth the effort.

Could be that Swiss customs takes ages to clear parcels. Could be that tax or import duties are complicated or simply just so high that it's not worth it. I knew a lot of people in Switzerland near the German border used to go shopping in Germany because was significantly cheaper, probably still the case today.

Not so much the case today that it is significantly cheaper because the Swiss Franc weak-end 7-8% in the last year to the Euro. Also, the German food is not comparable to Swiss food in quality. Example: Swiss meat is more expensive but then again it is from Switzerland and not form Poland (which can happen in Germany but not in Switzerland because of the tariffs on foreign meat).

Unlikely to be about Amazon experience. They currently offer Fire TV Basic to EU countries that don't have Amazon presence but they don't do so from within the EU from e.g. amazon.de but from amazon.com going through customs.

Amazon is doing a lot of this now, for example into India. They take a prepayment for duties, clear it for you and refund if it ended up costing less to clear.

Not really. Amazon charges you the import duty when you place the order. The only difference is that it takes a bit longer to get delivered.