Canned soup is cooked in the can in most cases so anything that may have evaporated away changing the taste is still sealed in the can. Also, when mass producing anything most companies will choose cheaper ingredients over higher quality ingredients.
So you’re left with a soup with low grade ingredients that’s still in the pot it was cooked in and never stirred, it’ll keep you alive but it didn’t have the same amount of effort put into it as someone cooking their own.