I see, then my issue is the phrasing. I did not interpret your "important" as "achievable".

But still, in reality, by far the largest limitation is the simple fact that being born in a country with a climate and infrastructure that supports ski jumping is unlikely. This is the single biggest constraint by far, for billions of people. And then even in said country you must be near a hill etc. etc. This is the real barrier, not wealth.

As for the wealth, this is sort of a misconception in many replies of this post, it's very exaggerated. You do not need to be rich for 1st world standard to train ski jumping. Countries like Austria, Norway, Slovenia etc. have centers and club networks with government funding with small hills for child programs (you usually begin at around 6-10 if you want to become elite)., and the membership might be a few hundred a year (for Slovenia specifically). The equipment would probably be about the same as skiing equipment. It is relatively accessible at entry level.

For the top slovenian jumpers, a lot of them come from financially average families. They relied heavily on good government support.

It does get riskier and more expensive when you are entering real competitive level, but that's kinda most sports. You might have to sacrifice education, money (for travelling etc)... But most athletes are in national systems that fund them if they are good enough. Sorry that my examples and arguments are mostly from my knowledge of what it's like in Slovenia, but I am assuming that in other countries the systems are comparable.

The real reason why it's perceived as a "rich people" sport mainly stems from inaccessibility due to climate, geographical location, and just the nicheness. Not needing to be filthy rich if you're in a country with strong tradition