Most current production tubes are made in Russia and China. The war in Ukraine and supply issues with China set off a wave of tube hoarding. In order to maintain a supply of tubes for their customers, some tube sellers have limited purchases and raised prices to keep from getting cleaned out.
It has been posted that Electro-Harmonix is still making tubes in Russia and they are not being sanctioned. Electro-Harmonix is owned by an American. China will eventually get back to full production and supply chain problems will get sorted out.
It’s a good idea to have a spare set of tubes on hand, but don’t go overboard and buy a bunch of tubes you may never use.