The tin can existed 45 years before the can opener.
In 1810 Peter Durand patented the tin can in England; Nicolas Appert had just developed preserving food by heating. The cans were thick-walled and heavy. Instructions: open with hammer and chisel. Only in 1855 did Robert Yeates in England patent a lever can opener, followed by Ezra Warner in the USA in 1858. Thinner tin made it worthwhile.
Useful: A product only becomes practical once the accessories around it exist.
Source: en.wikipedia.org