My uncle's old cast iron stove cracked one winter in Minnesota. He said the metal got too brittle from the deep freeze. I believe anvils can fail the same way.
My grandpa used to swear by cardboard for everything. He once made a whole temporary shed roof out of layered cardboard boxes and tar paper when a storm blew the real one off. Lasted three months until he got around to proper repairs. His whole shop was full of jury-rigged fixes like that, honestly more reliable than some fancy stuff you buy now. Guess the lesson is just to use what you have sometimes.