I read an article about this last month:
https://guitar.com/news/gear-news/pa...re-valve-amps/
There are all kinds of shortages out there right now. I was talking to the owner of a local business and he's having trouble sourcing simple things like lids for jars his product goes into. In Chicago the most popular maker of tortillas is having a shortage. Yes, a tortilla shortage. These are some uncertain times.