In the olden days the appellation, "amateur" distinguished the wealthy from
the working. Only the rich could afford to participate in the new sport of
track and field because they could afford it. But soon poor people wanted to
play too. The amateur organizations functioned to keep out stinky poor
people who might need to accept money for competing leaving the sport for
the clean aristocrats. But the aristocrats these days don't do track and
field, everyone showers, so amateur is no longer necessary to partition the
classes. Pithily put the words have reversed their meaning: the amateurs
were the competent owners and the professionals were the unskilled workers.
Now it's the opposite. These are funny things.
Tom Derderian, giggling in Boston