Why do we say that someone who inherited wealth was “born with a silver spoon in his mouth”?

If someone is “born with a silver spoon in his mouth,” it means that he
was born into wealth rather than having had to earn it. The expression
comes from an old custom of godparents giving the gift of a spoon to a
child at its christening to signify their responsibility for its nourishment
and well-being. If they were wealthy, the spoon was usually silver, and
if not, it would be pewter or tin.