The data that I looked at started with the 1967 season, which was the first World Cup season, and went through to 2014. My original thought was that as the number of races and disciplines increased, the number of all-around ski racers decreased. The criterion that I used was scoring points in every discipline in a season. It didn't matter if those were podium points or if the athlete only scored one point in a particular discipline. Back in the early days of the World Cup, it was harder to score points because only the top 10 racers earned them. That number increased to 15 in 1980 and 30 in 1992.
From 1967-79 ski racers competed in 3 disciplines: downhill, giant slalom and slalom. In 1980 super-combined was added as a separate discipline. Super-G was added in 1986. Before 1986 Super-G counted toward giant slalom points.
The chart below shows that as the number of races and disciplines increased, the number of racers who scored at least one point in every discipline decreased. There were two things that I found interesting:
1) Across all three time periods women tended to have more racers who scored points in every discipline in a season than the men, both in raw numbers and as a percentage of total racers with points.
2) For both women and men, the average number of athletes who could score points in every discipline in a season decreased by approximately 50% from 1967-79 to 1986-2014. The average percentage of those who scored points in every discipline compared to all skiers who scored World Cup points has decreased dramatically. I didn't run any tests to see if the numbers were statistically significant, but the phenomenon can easily be seen.
The ranges in each category are the high and low numbers for each period.
I was especially surprised by the men's results. Even though there were a few early years where there were 8 men who scored points in every discipline in a season, the men seemed to be either speed or technical specialists from the beginning of the World Cup. Across every era more women scored points in every discipline in a season, both in raw numbers and as a percentage of those who earned World Cup points.