IMC it's not uncommon for magic items to be destroyed. Our paladin is on his 4th longsword, and nearly lost that one yesterday, to a bunch of giant rust monsters. Each time he's lost a weapon, either we found or bought a replacement soon afterward, or he made do with a lower-powered weapon for a while. He was a little less effective, but not tremendously so.
Maybe we worry about it less because we don't keep track of cash separately. All treasure is owned by the party as a whole, and magic items go to whoever gets the most use out of them. Some characters have more valuable gear than others-- the sorcerer and paladin probably have the most, the monk has very little-- but everyone's effective in combat, and we don't waste time quibbling about how to divide the gold.
Maybe we worry about it less because we don't keep track of cash separately. All treasure is owned by the party as a whole, and magic items go to whoever gets the most use out of them. Some characters have more valuable gear than others-- the sorcerer and paladin probably have the most, the monk has very little-- but everyone's effective in combat, and we don't waste time quibbling about how to divide the gold.