That is completely wrong. Income is anything of value, not just cash. If you find a gold nugget in your yard, you have to pay taxes on the value of the gold even if you never sell it.
This all depends on juristication. You are correct if you implied the US AFAIK, TedDoesntTalk is right in e.g. Germany.
And even within the US this is true for the IRS but may or may not be true for the state in which the person lives.
They still owe the IRS regardless of state they live in though