Formaldehyde
Both Fair And Balanced
So when did this change? It seems to me like these days a lot of the athletes are professionals - they compete professionally in leagues, world cups, etc. The most obvious example of this are the hockey players - but you can also point to the ski jumpers, speed skaters, cross country skiiers, etc. I'm not really sure which winter sports do NOT have a lucrative league/world cup set up somewhere.. Curling, maybe? Some of the newer sports? Either way, when did this change, or have I just been mistaken when I was younger?
It all started with the skiers as you just mentioned. They have always been World Cup athletes for the most part who used to get paid under the table just so they could still compete in the Olympics. Back in the 60s, the monetary aspects started getting rather obvious, but everybody did their best to look the other way and try not to notice it. But even so, the competition was relatively fair and impartial. No country really benifited from it.
The next big impetus was the gross disparity caused by the Soviet Union and East Germany in particular developing professional Olympics programs for the propaganda value of winning so many medals. This caused the US and other countries to respond by cheating themselves. Both sides used a lot of athletes whose nominal job was "soldier", but all they did was prepare for the next Olympics or international competition. And the various national committees openly sponsored a number of other athletes from corporate and individual contributions.
Now, it is left up to each IF to determine the eligibility for each sport. Boxing is really the only sport left where no professionals compete, although that distinction is now getting muddied because a number of the "amateurs" now get funding from their local Olympics committees. Soccer uses the only 3 players over 23 rule to try to keep it in the spirit of amateur competition, instead of an all-out profest like hockey and basketball.
The original intent of the modern Olymics was to honor amateur sports. It was great while it lasted.